Re: Python, C++ interaction
Michael Kreim wrote: What are you using to wrap C++ classes for Python? I'm using SIP, as it fits nicely with my PyQt user interface. http://www.riverbankcomputing.com/software/sip/intro It's a pretty flexible and fast way of wrapping C++ and C. If you want to pass numpy arrays and such, it requires a bit more work, however. Jeremy -- https://mail.python.org/mailman/listinfo/python-list
Re: Python, C++ interaction
Am 03.12.14 09:29, schrieb Michael Kreim: I did some googleing on extending Python by C++ code but I did not find something that satisfies me. I gave SWIG a try, but several webpages disadvised me of using it. Also my small experiments did not work. I don't know why SWIG is discouraged; in my experience, it is a very easy way to generate the wrapping code around C++ classes, and also flexible in many directions. It can be easily extended for new datatypes (there is a numpy interface module, for instance), and also generates code for other scripting languages as well. What specifically did you try, and what failed? Concerning the callbacks, I don't know about these, but hopefully you are aware that you can easily loose the C++ speed advantage by using Python lambdas, since those have to go through the Python interpreter. Christian -- https://mail.python.org/mailman/listinfo/python-list
Re: Most gratuitous comments
In article 546d7505$0$12899$c3e8da3$54964...@news.astraweb.com, Steven D'Aprano st...@pearwood.info wrote: And the award for the most gratuitous comments before an import goes to one of my (former) workmates, who wrote this piece of code: # Used for base64-decoding. import base64 # Used for ungzipping. import gzip The comment lines contain genuine information. The program is decoding or gunzipping. (And apparently not doing the encoding part) This information may have been better conveyed by from base64 import base64-decode from gzip import gunzip but anyway. Also the comment may be misleading, but I think not. If there are mysterious names for packages, the comment may be actually useful. # Auxiliary for the reverse recursion to calculate # Chebychev coefficients. import courseware-2014-ch11 A professor who demands from students that every import is documented is IMO not to blame. In a company's coding convention ... I've seen a lot of things there that make a lot less sense. -- Steven -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spearc.xs4all.nl =n http://home.hccnet.nl/a.w.m.van.der.horst -- https://mail.python.org/mailman/listinfo/python-list
Re: Python, C++ interaction
Dan Stromberg drsali...@gmail.com wrote: 1) writing in Cython+CPython (as opposed to wrapping C++ with Cython) That is an option, but it locks the code to Cython and CPython forever. C and C++ are at least semi-portable. 2) using numba+CPython (It's a pretty fast decorator - I've heard it's faster than Cython) Numba is usually not faster than Cython (Cython can be as fast as C), but it can be pretty fast. Sometimes it is comparable to -O2 in C for the subset of Python it supports, but usually a bit slower. But if you can use it, it is easier to use than Cython. There are no extra compilation steps, etc. Just add a couple of decorators to the Python code and it takes off like a rocket. For anyone who are familiar with PyPy and Psyco, Numba is far better than those. It is a Python JIT compiler that often can perform better than the Java VM. Numba will also JIT-compile Python code that uses ctypes or cffi to call external libraries down to almost zero overhead. You forgot to mention using Fortran and f2py. Many scientists and engineers prefer Fortran to C and C++ because it is easier to use. And Fortran 90 and later standards are not anything like the loathed Fortran 66 and 77 languages. Fortran is a high-level language particularly suited for numerical computing, C is a semi-portable high-level assembler. Sturla -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
In article mailman.16378.1417111312.18130.python-l...@python.org, Peter Otten __pete...@web.de wrote: Albert van der Horst wrote: In the Rosetta code I come across this part of LU-decomposition. def pivotize(m): Creates the pivoting matrix for m. n = len(m) ID = [[float(i == j) for i in xrange(n)] for j in xrange(n)] for j in xrange(n): row = max(xrange(j, n), key=lambda i: abs(m[i][j])) if j != row: ID[j], ID[row] = ID[row], ID[j] return ID That it's using a cast from boolean to float and using at the other moment a float as a boolean, suggest that this code is a bit too clever for its own good, but anyway. My problem is with the max. I never saw a max with a key. In my python help(max) doesn't explain the key. It says that max can handle an iterator (I didn't know that), and you can pass and optional key=func, but that's all. I expect it to be something like elements in the iterator are taken into account only if the key applied to the iterator evaluates to a True value. However that doesn't pan out: max(xrange(100,200), key=lambda i: i%17==0 ) 102 I expect the maximum number that is divisible by 17 in the range, not the minimum. Can anyone shed light on this? Given a function f() max(items, key=f) returns the element of the `items` sequence with the greatest f(element), e. g. for max([a, bcd, ef], key=len) the values 1, 3, 2 are calculated and the longest string in the list is returned: max([a, bcd, ef], key=len) 'bcd' If there is more than one item with the maximum calculated the first is given, so for your attempt max(xrange(100,200), key=lambda i: i%17==0 ) the values False, False, True, False, ... are calculated and because True False True the first one with a True result is returned. So in that case max doesn't return the maximum (True), but instead something else. Useful as that function may be, it shouldn't have been called max. I don't blame myself for being misled. Groetjes Albert -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spearc.xs4all.nl =n http://home.hccnet.nl/a.w.m.van.der.horst -- https://mail.python.org/mailman/listinfo/python-list
Re: Python handles globals badly.
How can Skybuck use so much globals. Wouldn't that introduce a lot of thread safety problems? On Thu, Dec 4, 2014 at 9:32 AM, Mark Lawrence breamore...@yahoo.co.uk wrote: On 03/12/2014 23:02, Skybuck Flying wrote: Mark Lawrence wrote in message news:mailman.16534.1417610132.18130.python-l...@python.org... On 03/12/2014 02:27, Skybuck Flying wrote: Excuse is: bad programming style. I don't need snot telling me how to program after 20 years of programming experience. This is so far the only thing pissing me off in python. Now I have to declare global in front of these variables every where I want to use em: This reminds of of a quote from a colleague some 25 years ago Real time programming is easy, you just make all the data global. Perhaps you attended the same school? Another example of a bad workman always blames his tools. Euhm, so why don't you program with just 0 and 1's then ? ;) I did with the M6800 in the late 70s. Thankfully maybe 12 years ago I came across Python and it was love at first sight. I've never looked back. -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list -- Freelance Grails http://grails.asia/ and Java http://javadevnotes.com/ developer -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
On Thu, Dec 4, 2014 at 9:09 PM, Albert van der Horst alb...@spenarnc.xs4all.nl wrote: If there is more than one item with the maximum calculated the first is given, so for your attempt max(xrange(100,200), key=lambda i: i%17==0 ) the values False, False, True, False, ... are calculated and because True False True the first one with a True result is returned. So in that case max doesn't return the maximum (True), but instead something else. Useful as that function may be, it shouldn't have been called max. I don't blame myself for being misled. If lots of them are equally the largest, by whatever definition of largest you have, it has to do one of three things: 1) Raise an exception 2) Return multiple items (either as a tuple, or a generator, or something) 3) Pick one of them and return it. Python's max() does the third, and for the picking part, uses the first one it comes across - a decent way to do it. If there's no clear maximum, it can't do any better than that. It's still returning something for which there is no greater. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Python handles globals badly.
On 04/12/2014 05:03, jtan wrote: How can Skybuck use so much globals. Wouldn't that introduce a lot of thread safety problems? I actually don't know. However buying very strong thread from your local store and making sure that you have a very sharp needle does help alleviate threading safety problems. I do know that using globals is almost as bad as top posting on this list. -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: Python handles globals badly.
On Thu, Dec 4, 2014 at 4:03 PM, jtan ad...@grails.asia wrote: How can Skybuck use so much globals. Wouldn't that introduce a lot of thread safety problems? A lot of programs don't use threads, and therefore cannot have thread safety problems - or, looking at it the other way, do not care about thread safetiness. It's like having Neil Armstrong wear water wings to make sure he won't drown in the Sea of Tranquility. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Python docs disappointing
In article mailman.16030.1416502295.18130.python-l...@python.org, Joel Goldstick joel.goldst...@gmail.com wrote: SNIP Or just WOW!. Programming is hard, and people have just started to do it. Fifty years isn't that long. It has only been 20 years or so that the web has been around. That makes it easier to find information from a variety or sources -- the official docs, tutorials, articles. If you feel the docs are awful, write a tutorial based on your knowledge level and experience. Improve the situation. That doesn't help. I'm a very experienced programmer and work in routinely a dozen languages. Sometimes I do python. I want to do numeric work. I remember the name numpy. It is important, everybody knows it, it is all over the place. So I want to find its docs, or some lead, whatever. I go to the official Python site, http://docs.python.org and type in numpy in the search machine. It is embarassing, try it! Plain google is far superior in finding information. And you tell me that writing yet another tutorial would improve that? No, there is just one way. The powers that be should look critically at their website, and test it with a beginners hat on. I'm trying to wrap my mind around DOCUMENTION being STUPID. -- Joel Goldstick http://joelgoldstick.com Groetjes Albert -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spearc.xs4all.nl =n http://home.hccnet.nl/a.w.m.van.der.horst -- https://mail.python.org/mailman/listinfo/python-list
Re: Python docs disappointing
On Thu, Dec 4, 2014 at 9:27 PM, Albert van der Horst alb...@spenarnc.xs4all.nl wrote: That doesn't help. I'm a very experienced programmer and work in routinely a dozen languages. Sometimes I do python. I want to do numeric work. I remember the name numpy. It is important, everybody knows it, it is all over the place. So I want to find its docs, or some lead, whatever. I go to the official Python site, http://docs.python.org and type in numpy in the search machine. It is embarassing, try it! Plain google is far superior in finding information. Part of getting to know a language is learning what the best way to find information about it is. When I want Pike documentation, I always go direct to the docs (usually to my own build of them, to be sure it'll match my locally-compiled Pike, so that's http://sikorsky:8080/modref/index.html), but for most other languages, it's better to use a web search. Sometimes your best result isn't the official docs at all, but a StackOverflow post. Or maybe it's part of the official docs, but not the module reference page (if you want to know about argparse basics, the python.org howto is probably better than the main page). As an added bonus, you don't need to go here, type this into search - you just type what you want into your browser's search box, or at very worst, pull up a link you probably use a hundred times a day and will be cached. And you tell me that writing yet another tutorial would improve that? No, there is just one way. The powers that be should look critically at their website, and test it with a beginners hat on. The powers that be implies that there's somebody else who is obligated to provide a service to you. I don't think that's really the case. That said, though, your other points are quite right; another tutorial won't help, and improving search will help. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
In article mailman.16552.1417688329.18130.python-l...@python.org, Chris Angelico ros...@gmail.com wrote: On Thu, Dec 4, 2014 at 9:09 PM, Albert van der Horst alb...@spenarnc.xs4all.nl wrote: If there is more than one item with the maximum calculated the first is given, so for your attempt max(xrange(100,200), key=lambda i: i%17==0 ) the values False, False, True, False, ... are calculated and because True False True the first one with a True result is returned. So in that case max doesn't return the maximum (True), but instead something else. Useful as that function may be, it shouldn't have been called max. I don't blame myself for being misled. If lots of them are equally the largest, by whatever definition of largest you have, it has to do one of three things: 1) Raise an exception 2) Return multiple items (either as a tuple, or a generator, or something) 3) Pick one of them and return it. Python's max() does the third, and for the picking part, uses the first one it comes across - a decent way to do it. If there's no clear maximum, it can't do any better than that. It's still returning something for which there is no greater. I agree that it is a useful function and that it is doing the right thing. What is wrong is the name. I refer to the fact that it is not returning the maximum. It returns the iterator value that leads to the maximum. A function that doesn't return a maximum shouldn't be called maximum. ChrisA -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spearc.xs4all.nl =n http://home.hccnet.nl/a.w.m.van.der.horst -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
Albert van der Horst writes: Useful as that function [Python's max with a key] may be, it shouldn't have been called max. The meaning of the key should be added to help(max), if it still isn't - returns a maximal element or an element that maximizes the key. In some communities they call it arg max, with a thin space between the components of the name. Or maybe no space: argmax. Would you also want sorted called something else when used with a key? Because it doesn't produce a sorted list of the keys either: data = (short, long, average) sorted(data, key=len) ['long', 'short', 'average'] max(data, key=len) 'average' sorted(map(len, data)) [4, 5, 7] max(map(len, data)) 7 While the key is not a filter, a filter is as available as the map above: max(filter(lambda i : i % 17 == 0, range(100, 200))) 187 -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
Albert van der Horst writes: Chris Angelico wrote: If there's no clear maximum, it can't do any better than that. It's still returning something for which there is no greater. I agree that it is a useful function and that it is doing the right thing. What is wrong is the name. I refer to the fact that it is not returning the maximum. It returns the iterator value that leads to the maximum. A function that doesn't return a maximum shouldn't be called maximum. It's called max. A maximal element need not be unique even in mathematics: http://en.wikipedia.org/wiki/Maximal_element. -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
Albert van der Horst wrote: In article mailman.16378.1417111312.18130.python-l...@python.org, Peter Otten __pete...@web.de wrote: Albert van der Horst wrote: In the Rosetta code I come across this part of LU-decomposition. def pivotize(m): Creates the pivoting matrix for m. n = len(m) ID = [[float(i == j) for i in xrange(n)] for j in xrange(n)] for j in xrange(n): row = max(xrange(j, n), key=lambda i: abs(m[i][j])) if j != row: ID[j], ID[row] = ID[row], ID[j] return ID That it's using a cast from boolean to float and using at the other moment a float as a boolean, suggest that this code is a bit too clever for its own good, but anyway. My problem is with the max. I never saw a max with a key. In my python help(max) doesn't explain the key. It says that max can handle an iterator (I didn't know that), and you can pass and optional key=func, but that's all. I expect it to be something like elements in the iterator are taken into account only if the key applied to the iterator evaluates to a True value. However that doesn't pan out: max(xrange(100,200), key=lambda i: i%17==0 ) 102 I expect the maximum number that is divisible by 17 in the range, not the minimum. Can anyone shed light on this? Given a function f() max(items, key=f) returns the element of the `items` sequence with the greatest f(element), e. g. for max([a, bcd, ef], key=len) the values 1, 3, 2 are calculated and the longest string in the list is returned: max([a, bcd, ef], key=len) 'bcd' If there is more than one item with the maximum calculated the first is given, so for your attempt max(xrange(100,200), key=lambda i: i%17==0 ) the values False, False, True, False, ... are calculated and because True False True the first one with a True result is returned. So in that case max doesn't return the maximum (True), but instead something else. Useful as that function may be, it shouldn't have been called max. I don't blame myself for being misled. I believe you still misunderstand. Again, this time with an almost real- world car example: max(values key=key) calculates key(value) for every value in values. key() can be len() or an attribute getter, so that max(cars, key=lambda car: car.weight) finds the heaviest car and max(cars, key=lambda car: car.speed) finds the fastest car. (If there is a tie the first car with maximum weight/speed is returned.) The advantage of this approach is that you don't have to choose a natural order, i. e. should max(cars) find the fastest, or the heaviest, or the [you name it] car? Also, you are really interested in the car, and max(car.speed for car in cars) would only give you the speed of the fastest car, not the car object itself. To find the fastest car without a key argument you'd have to write fastest_car = max((car.speed, car) for car in cars)[-1] or even fastest_car = max((car.speed, i, car) for (i, car) in enumerate(cars))[-1] if you are thorough and want the first car in the sequence with maximum speed or have to deal with car objects that aren't comparable. The example where the key returns a boolean value is very uncommon, but booleans are not treated specially. So while you can write first_red_car = max(cars, key=lambda car: car.color == RED) if first_red_car.color == RED: print(first_red_car) else: print(no red cars available) that is unidiomatic. It is also inefficient because max() always iterates over the whole cars sequence in search for an even redder car. False == 0, and True == 1, and max() cannot be sure that the key function will never return 2 or TruerThanTrue ;) -- but the programmer usually knows. Better: red_cars = (car for car in cars if car.color == RED) first_red_car = next(red_cars, None) if first_red_car is not None: print(first_red_car) else: print(no red cars available) PS: Another thing to consider is the similarity with sorted(). You can sort by speed sorted(cars, key=lambda car: car.speed) or redness sorted(cars, key=lambda car: car.color == RED) but you will see the former much more often than the latter. -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
Albert van der Horst wrote: I agree that it is a useful function and that it is doing the right thing. What is wrong is the name. I refer to the fact that it is not returning the maximum. It returns the iterator value that leads to the maximum. A function that doesn't return a maximum shouldn't be called maximum. But a maximum is often ambiguous. What is max(people), the oldest, tallest, or richest person? The key argument is a convenient way to disambiguate. -- https://mail.python.org/mailman/listinfo/python-list
Re: Python handles globals badly.
jtan wrote: How can Skybuck use so much globals. Wouldn't that introduce a lot of thread safety problems? Of course it would. But I expect that Skybuck probably doesn't even know what threads are. Or if he does, he probably doesn't believe that they should be used. Thread safety is just the start of the problems with global variables: http://c2.com/cgi/wiki?GlobalVariablesAreBad Globals in Python are less bad than in many other languages, since they are localised to a single module only. And the use of a few globals here and there as needed is perfectly fine for small scripts. But using dozens of them to avoid passing arguments to functions, that's just awful code. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: Python docs disappointing
Albert van der Horst wrote: That doesn't help. I'm a very experienced programmer and work in routinely a dozen languages. Sometimes I do python. I want to do numeric work. I remember the name numpy. It is important, everybody knows it, it is all over the place. So I want to find its docs, or some lead, whatever. I go to the official Python site, http://docs.python.org and type in numpy in the search machine. It is embarassing, try it! Why would it be embarrassing? Why should the Python website provide documentation for numpy? Numpy is not part of the Python language, and it is not part of the Python standard library. If you buy a Compaq printer to plug in to your Hewlett-Packard computer running Windows, would you go to the Microsoft website to find out where to order toner for the printer? Or to the H-P site? Numpy might be written *in* Python (*some* of numpy, not all of it) but it is not part of Python. Why should the python language website be responsible for numpy documentation? How about django, CherryPy, nltk, and about two thousand other third party projects? It is 2014, not 1977, and your first step for nearly any search should be the global search engine of your choice: Google, DuckDuckGo, Bing, Yahoo, Startpage, or similar. Only if you know that something is categorically part of Python or its standard library should you limit yourself to the Python language reference and standard library documentation. Plain google is far superior in finding information. Well duh. And you tell me that writing yet another tutorial would improve that? Apparently people need a tutorial to teach them to search the entire web not just a single website... -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
Jussi Piitulainen wrote: Would you also want sorted called something else when used with a key? Because it doesn't produce a sorted list of the keys either: data = (short, long, average) sorted(data, key=len) ['long', 'short', 'average'] max(data, key=len) 'average' I agree with the point you are making, but I disagree with the wording you use. The result of calling sort() with key=len *is* sorted. It is sorted by length of the word. Same for calling max() with a key. The result is still the maximum value. The difference is how you decide which of two elements is greater: max(list_of_foods, key=calories) max(list_of_foods, key=weight) max(list_of_foods, key=cost) That is three different ways to decide which is the maximal food in the list: by number of calories, by weight, or by cost. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
Albert van der Horst wrote: I agree that it is a useful function and that it is doing the right thing. What is wrong is the name. I refer to the fact that it is not returning the maximum. It returns the iterator value that leads to the maximum. That is incorrect. It returns the maximum value, that is, the value greater than all the other values. What is different is the way this value is greater than that value is tested for the purposes of calculating this maximum. A function that doesn't return a maximum shouldn't be called maximum. Naturally. But this does calculate the maximum, according to the given key function. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: Python handles globals badly.
Chris Angelico ros...@gmail.com: A lot of programs don't use threads, and therefore cannot have thread safety problems - or, looking at it the other way, do not care about thread safetiness. It's like having Neil Armstrong wear water wings to make sure he won't drown in the Sea of Tranquility. The water wings would be too unwieldy since they'd have to be six times as large on the moon. It's all about risk/benefit analysis. Marko -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
Steven D'Aprano writes: Jussi Piitulainen wrote: Would you also want sorted called something else when used with a key? Because it doesn't produce a sorted list of the keys either: data = (short, long, average) sorted(data, key=len) ['long', 'short', 'average'] max(data, key=len) 'average' I agree with the point you are making, but I disagree with the wording you use. The result of calling sort() with key=len *is* sorted. It is sorted by length of the word. It's sorted but it's not a list of the keys. That seemed to be a point of contention about naming max-with-key max: it doesn't return a key. Same for calling max() with a key. The result is still the maximum value. The difference is how you decide which of two elements is greater: max(list_of_foods, key=calories) max(list_of_foods, key=weight) max(list_of_foods, key=cost) That is three different ways to decide which is the maximal food in the list: by number of calories, by weight, or by cost. Yes. I don't see any disagreement between us. -- https://mail.python.org/mailman/listinfo/python-list
A question about setup.py
Hi I'm trying to install the path.py package under Python 2.7 on Windows. I installed it using: easy_install path.py That worked but it didn't install path.py which is needed by my PTVS IDE for code completion (Intellisense). I then tried downloading path.py-7.0.zip. I unzipped it and ran: python setup.py install within the extracted folder. But path.py still appears not to have been copied to: C:\Python27 What am I doing wrong? Best regards David -- https://mail.python.org/mailman/listinfo/python-list
Re: Most gratuitous comments
- Original Message -
From: sohcahto...@gmail.com
I was trying to illustrate the point that some professors would
demand you write code like this...
# increment the line count
lineCount += 1
# Check if line count is over 10
if lineCount 10
# Tell the user there are too many lines
print 'There are too many lines!
...which is obviously bad commenting style. But I guess my original
minimal example was too minimal.
The problem is not that every line is commented, the problem is that comments
do not add any value. There's always something to tell in real life situations:
# assuming all lines look like 'v=1234\n', generate all integers provided by
the user
values = (int(line.replace('v=', '')) for line in lines)
# See SPE-xxx: 10 line max do not change it
if len(lines) 10:
# TODO: use the logging module
print 'There are too many lines!
In practice, this yield to a comment every 2 or 3 lines. Of course this much
depend on the code itself and may vary slightly from code block to code block.
Note that I am not sanctioning the use of comment on import statements :D
To go back to your point, some professors may be right when asking a comment
every line, because it will be easier then for someone to back off a little bit
and comment slightly less. While students with the habit of writing no comment
will have much trouble commenting properly.
Cheers,
JM
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Re: How is max supposed to work, especially key.
On Thu, Dec 4, 2014, at 05:09, Albert van der Horst wrote: So in that case max doesn't return the maximum (True), but instead something else. If you want to find the largest item in a list of of strings, sorted case-insensitively, you might use str.lower or locale.strxfrm as the key function. If two strings are case-insensitively identical, using str.lower will return an arbitrary one (or maybe the first or last found in the original list), using locale.strxfrm will return the one that is in uppercase in the first position where they are different. But you don't want it to return the all-lowercase version (or the messy binary thing returned by strxfrm), you want it to return the string from the original list. Think of it this way: the key function returns a proxy object whose comparison operators compare according to the relationship you want to compare the originals by. Bool does not make a good proxy object. If you want to use the original as a tiebreaker, you might use lambda x: (str.lower(x), x). A key function is supposed to be a function that will always return the same result on the same input, so if you want to know the maximum [i.e. the actual key value that was compared by the max function] you can simply apply it again on the result. -- https://mail.python.org/mailman/listinfo/python-list
Re: Most gratuitous comments
Many years ago I, too, had a couple of CS profs who forced us to include too many (usually innocuous) comments in our Fortran and PL/1 code. Perhaps they were trying to counter the natural programmer tendency of not commenting at all? Forty years of programming later (yikes!), I try to use comments to tell WHY I'm doing what I'm doing, especially when it's not obvious to someone else (or to me in about two weeks). I never use comments to teach the reader what the Python language or libraries do. Cheers, Steve J. Martin -- https://mail.python.org/mailman/listinfo/python-list
time.monotonic() roll over
Hello, Does any body know when time.monotonic() rolls over ? On python doc https://docs.python.org/3/library/time.html it is said every 49.7 days on Windows versions older than Vista. For more recent Windows, it is sais that monotonic() is system-wide but they dont say anything about roll over, probably it hasn't changed. Anyway, if someone need a monotonic clock, he may think to use either time.time() or time.monotonic(). There is no roll over problem with time.time() since the very first one in planned far in the future, but time.time() can go backward when a date update throught NTP server is done. time.monotonic() is monotonic but roll over often (every 49.7 days) So what to do ? Using time.monotonic() and take some actions if a roll over is detected ? -- https://mail.python.org/mailman/listinfo/python-list
Re: PyEval_GetLocals and unreferenced variables
On Wed, Dec 3, 2014 at 5:28 AM, Gregory Ewing greg.ew...@canterbury.ac.nz wrote: Kasper Peeters wrote: That may have been the design plan, but in Python 2.7.6, I definitely am able to inject locals via PyEval_GetLocals() and have them be visible both from the C and Python side; What seems to be happening is that the dict created by PyEval_GetLocals() is kept around, so you can change it and have the changes be visible through locals() in Python. That the dict is cached is an implementation detail. It's not advisable to rely upon this, and as stated in the Python docs, the locals dict should not be modified. -- https://mail.python.org/mailman/listinfo/python-list
Re: How is max supposed to work, especially key.
On 12/4/2014 5:35 AM, Albert van der Horst wrote: I agree that it is a useful function and that it is doing the right thing. What is wrong is the name. I refer to the fact that it is not returning the maximum. It returns the iterator value that leads to the maximum. A function that doesn't return a maximum shouldn't be called maximum. The key function serves the same purpose as with sort. It define a custom ordering of items, not the values returned. 'x y' is defined as key(x) key(y), where the comparison of keys uses the standard (and for numbers, natural) built-in ordering. So max returns the max value according to the order you define with the key function. The default key is the identity function, so the default order is the builtin order. -- Terry Jan Reedy -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
ast nom...@invalid.com: Does any body know when time.monotonic() rolls over ? Never, according to the documentation you linked. Admittedly, the documentation confuses the reader by chatting about some irrelevant internal Windows details. Also, the tone of the documentation raises a suspicion that this code might return a bad value on Windows: def fifty_days(): a = time.monotonic() time.sleep(50 * 24 * 3600) return time.monotonic() - a That is, the internal integer wrap is not guarded against between the calls to time.monotonic(), maybe. Marko -- https://mail.python.org/mailman/listinfo/python-list
Re: Python handles globals badly.
I wish him all the luck while having sleep deprivation trying to solve production issues :) On Thu, Dec 4, 2014 at 7:35 PM, Steven D'Aprano steve+comp.lang.pyt...@pearwood.info wrote: jtan wrote: How can Skybuck use so much globals. Wouldn't that introduce a lot of thread safety problems? Of course it would. But I expect that Skybuck probably doesn't even know what threads are. Or if he does, he probably doesn't believe that they should be used. Thread safety is just the start of the problems with global variables: http://c2.com/cgi/wiki?GlobalVariablesAreBad Globals in Python are less bad than in many other languages, since they are localised to a single module only. And the use of a few globals here and there as needed is perfectly fine for small scripts. But using dozens of them to avoid passing arguments to functions, that's just awful code. -- Steven -- https://mail.python.org/mailman/listinfo/python-list -- Freelance Grails http://grails.asia/ and Java http://javadevnotes.com/ developer -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Dec 4, 2014 8:56 AM, Marko Rauhamaa ma...@pacujo.net wrote: ast nom...@invalid.com: Does any body know when time.monotonic() rolls over ? Never, according to the documentation you linked. Admittedly, the documentation confuses the reader by chatting about some irrelevant internal Windows details. Not entirely irrelevant. The implication is that if you go more than 49 days without calling the function on old Windows systems, rollovers could be missed, which is good to know about. The result would still be monotonic, but it wouldn't accurately reflect the time elapsed. -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Fri, Dec 5, 2014 at 3:05 AM, Ian Kelly ian.g.ke...@gmail.com wrote: On Dec 4, 2014 8:56 AM, Marko Rauhamaa ma...@pacujo.net wrote: ast nom...@invalid.com: Does any body know when time.monotonic() rolls over ? Never, according to the documentation you linked. Admittedly, the documentation confuses the reader by chatting about some irrelevant internal Windows details. Not entirely irrelevant. The implication is that if you go more than 49 days without calling the function on old Windows systems, rollovers could be missed, which is good to know about. The result would still be monotonic, but it wouldn't accurately reflect the time elapsed. I don't know for sure about the newer Windowses, but I believe they use a 64-bit counter instead of the 32-bit one used in previous versions, so even if they do roll over, there'll be a much MUCH longer time scale involved. Even if it stores time in nanoseconds, a 64-bit counter would allow for hundreds of years between rollovers, which is reasonably safe - much better than the month-and-a-bit of older ones, which is shorter than quite a lot of my programs' uptimes. Hence the lack of information about them; you don't have to worry. (Likewise on Unix-derived systems, I believe, and for the same reason.) ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
Ian Kelly ian.g.ke...@gmail.com: The implication is that if you go more than 49 days without calling the function on old Windows systems, rollovers could be missed, which is good to know about. The implication is all but clear, but that was my suspicion. It would be so bad that the documentation should be much more explicit about it. No, that would be a Python standard library bug, period. Marko -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Fri, Dec 5, 2014 at 3:21 AM, Marko Rauhamaa ma...@pacujo.net wrote: Ian Kelly ian.g.ke...@gmail.com: The implication is that if you go more than 49 days without calling the function on old Windows systems, rollovers could be missed, which is good to know about. The implication is all but clear, but that was my suspicion. It would be so bad that the documentation should be much more explicit about it. No, that would be a Python standard library bug, period. It's not a Python issue. Python can't do anything more than ask the system, and if the system's value rolls over several times a year, Python can't magically cure that. The information has already been lost. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Is Python installer/un-installer buggy on Windows?
Yeah, the problem seems to be with registry as every solution seems to be fiddling with registry. I know that reinstalling OS is a really bad idea. But I have tried to find a way to solve this for months now. I have started a bounty on superuser also for the same in the question Python IDLE disappeared from the right click context menu. And asking on these groups was the last thing I can think of. I uninstalled via the Control Panel. I installed via the official Python installer for Windows. I also don't understand how a start menu entry can begin an installation but it is doing just that. Now there seems to be 4 IDLE entries in my start menu. Two are valid (2.7.8, 3.4.2). The other two are previous installations of Python 3.4 that I did at different locations but removed later. I have stopped running IDLE from the start menu due to this. Because I am never sure whether it will re-install Python 3.4 at those old locations or not. Even right clicking those entries in start menu causes the installations to start. So I cannot even find the physical path of those entries. Maybe too much fiddling with the registry has caused it. Not sure about that. -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Thu, Dec 4, 2014, at 10:50, Marko Rauhamaa wrote: That is, the internal integer wrap is not guarded against between the calls to time.monotonic(), maybe. Looking at the code, it looks like it does guard against the rollover, though if you let your program run for 49.7 days _without_ calling time.monotonic during that time, it will not realize that it has passed the original value multiple times. And of course, if it rolls over before the first time you call monotonic in process B, process B's value will be less than process A which called it before the rollover. This is consistent with the documentation, and appears to be the reason the documentation discusses this issue at all. -- https://mail.python.org/mailman/listinfo/python-list
Do you like the current design of python.org?
Did you ever hit the Socialize button? Are you eager to see the latest tweets when you are reading a PEP? Do you run away screaming from a page where nothing moves without you hitting a button? Do you appreciate the choice between ten or so links to the documentation? You can probably guess my opinion -- konqueror just crashed on the PEP index and for some reason I'm more annoyed about the page than about the browser. PS: Is there a twitter.com something that I can block to trade black friday and cyber monkey sales for a box with a good old error message? -- https://mail.python.org/mailman/listinfo/python-list
Re: Most gratuitous comments
On 04 Dec 2014 09:48:49 GMT alb...@spenarnc.xs4all.nl (Albert van der Horst) wrote: In article 546d7505$0$12899$c3e8da3$54964...@news.astraweb.com, Steven D'Aprano st...@pearwood.info wrote: And the award for the most gratuitous comments before an import goes to one of my (former) workmates, who wrote this piece of code: # Used for base64-decoding. import base64 # Used for ungzipping. import gzip The comment lines contain genuine information. The program is decoding or gunzipping. (And apparently not doing the encoding part) This information may have been better conveyed by from base64 import base64-decode from gzip import gunzip but anyway. Also the comment may be misleading, but I think not. If there are mysterious names for packages, the comment may be actually useful. # Auxiliary for the reverse recursion to calculate # Chebychev coefficients. import courseware-2014-ch11 A professor who demands from students that every import is documented is IMO not to blame. In a company's coding convention ... I've seen a lot of things there that make a lot less sense. -- Steven -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spearc.xs4all.nl =n http://home.hccnet.nl/a.w.m.van.der.horst In my code, I habitually use big old bar comments to break the imports into three sections, standard library, third-party libraries, and local imports. I find it radically simplifies knowing where to start looking for documentation. -- Rob Gaddi, Highland Technology -- www.highlandtechnology.com Email address domain is currently out of order. See above to fix. -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
On 12/03/2014 12:02 PM, Chris Angelico wrote: When importing a module from a subpackage, it's sometimes convenient to refer to it throughout the code with a one-part name rather than two. I'm going to use 'os.path' for the examples, but my actual use-case is a custom package where the package name is, in the application, quite superfluous. Throughout the code, I want to refer to path.split(), path.isfile(), etc, without the os. in front of them. I could do either of these: import os.path as path from os import path Which one would you recommend? Does it depend on context? One argument not yet brought up by anyone else: if you ever wanted to make the module part of your own package and turn the import into a relative one, only the second, but not the first form lets you replace the package name with . : from . import path (while import .path is a SyntaxError, so you'd need a slightly more complicated rewrite). Wolfgang -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
- Original Message - From: Chris Angelico ros...@gmail.com To: python-list@python.org Sent: Wednesday, 3 December, 2014 12:02:17 PM Subject: Style question: Importing modules from packages - 'from' vs 'as' When importing a module from a subpackage, it's sometimes convenient to refer to it throughout the code with a one-part name rather than two. I'm going to use 'os.path' for the examples, but my actual use-case is a custom package where the package name is, in the application, quite superfluous. Throughout the code, I want to refer to path.split(), path.isfile(), etc, without the os. in front of them. I could do either of these: import os.path as path from os import path Which one would you recommend? Does it depend on context? An as import works only if it's a module in a package, where the from import can also import other objects (you can't go import pprint.pprint as pprint). I'm fairly sure that's an argument... on one side or another. :) Thoughts? ChrisA -- https://mail.python.org/mailman/listinfo/python-list I know you specifically stated you didn't want to do this but import os os.path.isfile() is the best option imo, especially from the reader point of view (Namespaces are one honking great idea). -- IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
On 12/04/2014 09:36 AM, Jean-Michel Pichavant wrote: I know you specifically stated you didn't want to do this but import os os.path.isfile() is the best option imo, especially from the reader point of view (Namespaces are one honking great idea). But, Flat is better than nested ! ;) -- ~Ethan~ signature.asc Description: OpenPGP digital signature -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
On 12/03/2014 03:02 AM, Chris Angelico wrote: Throughout the code, I want to refer to path.split(), path.isfile(), etc, without the os. in front of them. I could do either of these: import os.path as path from os import path Which one would you recommend? Does it depend on context? I recommend the one with less typing. ;) -- ~Ethan~ signature.asc Description: OpenPGP digital signature -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
On Fri, Dec 5, 2014 at 4:36 AM, Jean-Michel Pichavant jeanmic...@sequans.com wrote: I know you specifically stated you didn't want to do this but import os os.path.isfile() is the best option imo, especially from the reader point of view (Namespaces are one honking great idea). With os.path it definitely is. With the actual code in question, it's a Python 2.7 project that mostly uses relative imports - inside package.module1 is import module2 etc - and I was writing an external script that calls on one of the modules. So it makes sense to reference it through the code the exact same way, as module.blah rather than package.module.blah. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
Chris Angelico ros...@gmail.com: It's not a Python issue. Python can't do anything more than ask the system, and if the system's value rolls over several times a year, Python can't magically cure that. The information has already been lost. Sure it could by having an invisible background thread occasionally call time.monotonic(). It could even be done on the side without a thread. Anyway, the idea of a clock is complicated: * the program could be stopped by a STOP signal * the program could be suspended from power management * the program could be resurrected from a virtual machine snapshot * the program could be migrated from a different physical machine So, if I call time.sleep(86400) and the program is suspended for 24 hours, should time.sleep() return right after it is resumed or after another 24 hours? Marko -- https://mail.python.org/mailman/listinfo/python-list
ORM opinion
Begrudgingly, I need to migrate away from SQLAlchemy onto a package that has fast imports and very fast model build times. I have a less than ideal application that uses Python as a plugin interpreter which is not performant in this use case where its being invoked freshly several times per operation within the application where several operations themselves are queued. In order to minimize latency, I need to remove anything that either takes a noticeable amount of time to import or run. My initial backend support is limited to only SQLite. Anyone have any recos or opinions? Thanks, jlc -- https://mail.python.org/mailman/listinfo/python-list
Re: Do you like the current design of python.org?
On 12/04/2014 09:09 AM, Peter Otten wrote: Did you ever hit the Socialize button? Are you eager to see the latest tweets when you are reading a PEP? Do you run away screaming from a page where nothing moves without you hitting a button? Do you appreciate the choice between ten or so links to the documentation? You can probably guess my opinion -- konqueror just crashed on the PEP index and for some reason I'm more annoyed about the page than about the browser. Visually, it's nice; functionally... well, I just had to use google to find the CLA form, because the built-in search box couldn't (and yes, it's on the site). -- ~Ethan~ signature.asc Description: OpenPGP digital signature -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Fri, Dec 5, 2014 at 5:09 AM, Marko Rauhamaa ma...@pacujo.net wrote: Sure it could by having an invisible background thread occasionally call time.monotonic(). It could even be done on the side without a thread. No, it can't be solved by anything in that process, because... * the program could be stopped by a STOP signal ... what you said There's no way to guarantee to keep calling the function. You have to depend on upstream. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: ORM opinion
On Fri, Dec 5, 2014 at 5:14 AM, Joseph L. Casale jcas...@activenetwerx.com wrote: Begrudgingly, I need to migrate away from SQLAlchemy onto a package that has fast imports and very fast model build times. I have a less than ideal application that uses Python as a plugin interpreter which is not performant in this use case where its being invoked freshly several times per operation within the application where several operations themselves are queued. In order to minimize latency, I need to remove anything that either takes a noticeable amount of time to import or run. My initial backend support is limited to only SQLite. Anyone have any recos or opinions? First recommendation: Less layers. Instead of SQLAlchemy, just import sqlite3 and use it directly. You should be able to switch out import sqlite as db for import psycopg2 as db or any other Python DB API module, and still have most/all of the benefit of the extra layer, without any extra imports. Secondly, see if you can keep the Python process running, instead of separately invoking it for every operation. This will mean some structural changes, but if you're specifying Python as the plugin interpreter (as opposed to, say, execute this program with these args, which is far more general), you can probably set up a wrapper script that calls on the user code repeatedly. Perhaps you could have a multiprocessing.Queue feeding tasks to the subprocess, via a little parent Python process. If you can't make those kinds of changes to the application, the next best would be a stubby driver process that feeds jobs to your real subprocess; the real work might be done by a Unix/TCP socket server, and the stub connects, feeds it some information, gets back a result, and disconnects. The stub will have an extremely minimal set of imports (the bear necessities of life, if you like), and the real process can import as much as it likes, because it won't be doing it for every operation. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
Chris Angelico ros...@gmail.com: ... what you said There's no way to guarantee to keep calling the function. You have to depend on upstream. The caveats I listed are real concerns for the modern-day programmer. However, they are of a different nature than the complaint against time.monotonic(). Marko -- https://mail.python.org/mailman/listinfo/python-list
Not Able to Log in on XNAT server through PyXNAT
Hello All, I have installed pyxnat on my mac. With pyxnat i am trying to access XNAT server in our university. As mentioned on the tutorial i tried both ways, neither is working. Following error is displayed: central=Interface(server='http://hd-hni-xnat.cac.cornell.edu:8443/xnat') User: sdb99 Password: Traceback (most recent call last): File stdin, line 1, in module File /Library/Python/2.7/site-packages/pyxnat/core/interfaces.py, line 228, in __init__ self._get_entry_point() File /Library/Python/2.7/site-packages/pyxnat/core/interfaces.py, line 268, in _get_entry_point raise e socket.error: [Errno 54] Connection reset by peer Before accessing XNAT using REST API, do i need to make any changes/install something on XNAT server/my pc(have installed Pyxnat)..? Many Thanks in Advance.. Suyash -- https://mail.python.org/mailman/listinfo/python-list
Re: Can you use self in __str__
- Original Message -
From: Seymore4Head Seymore4Head@Hotmail.invalid
To: python-list@python.org
Sent: Friday, 28 November, 2014 4:31:50 AM
Subject: Re: Can you use self in __str__
On Thu, 27 Nov 2014 21:49:29 -0500, Dave Angel da...@davea.name
wrote:
class Hand:
def __init__(self):
self.hand = []
# create Hand object
def __str__(self):
s = 'Hand contains '
for x in self.hand:
s = s + str(x) +
return s
I am using 2.7 (Codeskulptor). This is working code. It starts with
an empty list that gets appended from a full deck of shuffled cards.
dealer=Hand()
player=Hand()
I don't really know how to post working code without posting a lot.
I
am not being too successful in trying to post enough code to have it
work without posting the entire code.
Here is the link if you want to run it.
http://www.codeskulptor.org/#user38_Kka7mh2v9u_9.py
The print out looks like this:
Hand contains H4 DQ.
I can (and am) currently printing the hand like this:
print Player's,player
print Dealer's,dealer
My question is can you add (self) in the __str__ so when you issue
the
command print player the player part is included in the __str__.
--
https://mail.python.org/mailman/listinfo/python-list
I think your main problem is a design issue.
I won't go into details, it would be too long but here's a way to fix your
problem:
# Untested code
class Player(object):
def __init__(self, name):
self.name = name
self.hand = Hand()
def __str__(self):
return '%s%s has %s' % (self.__class__.__name__, self.name, self.hand)
# A dealer is a special type of player
class Dealer(Player): pass
def deal():
global outcome, in_play,deck,dealer,player
# your code goes here
deck=Deck()
deck.shuffle()
print deck
players = [Dealer('Robert'), Player('John')]
for deal in range(2):
for player in players:
player.hand.add_card(deck.deal_card())
for player in players:
print str(player)
in_play = True
With the above design, the relation between player and its hand is implemented
with the Player attribute hand.
It's a classic design where the container knows about the content, but the
content does not know its container.
There are other solutions which do not require a new class, but I have the
feeling you will need the Player class in the future.
Moreover The design above I gave you will be probably broken in the future when
you add features to your code.
The same player may be a dealer or not, it may vary over time. You will
probably need a 'Table' object which handles a collection of players, with a
dealer, small blind, big blind etc, amount of money in the pot etc...
JM
-- IMPORTANT NOTICE:
The contents of this email and any attachments are confidential and may also be
privileged. If you are not the intended recipient, please notify the sender
immediately and do not disclose the contents to any other person, use it for
any purpose, or store or copy the information in any medium. Thank you.
--
https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Thu, Dec 4, 2014 at 11:09 AM, Marko Rauhamaa ma...@pacujo.net wrote: Chris Angelico ros...@gmail.com: It's not a Python issue. Python can't do anything more than ask the system, and if the system's value rolls over several times a year, Python can't magically cure that. The information has already been lost. Sure it could by having an invisible background thread occasionally call time.monotonic(). It could even be done on the side without a thread. Anyway, the idea of a clock is complicated: * the program could be stopped by a STOP signal * the program could be suspended from power management * the program could be resurrected from a virtual machine snapshot * the program could be migrated from a different physical machine This seems like a lot of effort to unreliably design around a problem that will matter to only a tiny fraction of users. -- https://mail.python.org/mailman/listinfo/python-list
Re: Do you like the current design of python.org?
Peter Otten __pete...@web.de writes: Did you ever hit the Socialize button? Are you eager to see the latest tweets when you are reading a PEP? Do you run away screaming from a page where nothing moves without you hitting a button? Do you appreciate the choice between ten or so links to the documentation? You can probably guess my opinion -- konqueror just crashed on the PEP index and for some reason I'm more annoyed about the page than about the browser. PS: Is there a twitter.com something that I can block to trade black friday and cyber monkey sales for a box with a good old error message? I see that pythondotorg accepts pull requests and allows to report issues. https://github.com/python/pythondotorg -- Akira -- https://mail.python.org/mailman/listinfo/python-list
Re: Can you use self in __str__
On Thu, 4 Dec 2014 20:22:11 +0100 (CET), Jean-Michel Pichavant
jeanmic...@sequans.com wrote:
- Original Message -
From: Seymore4Head Seymore4Head@Hotmail.invalid
To: python-list@python.org
Sent: Friday, 28 November, 2014 4:31:50 AM
Subject: Re: Can you use self in __str__
On Thu, 27 Nov 2014 21:49:29 -0500, Dave Angel da...@davea.name
wrote:
class Hand:
def __init__(self):
self.hand = []
# create Hand object
def __str__(self):
s = 'Hand contains '
for x in self.hand:
s = s + str(x) +
return s
I am using 2.7 (Codeskulptor). This is working code. It starts with
an empty list that gets appended from a full deck of shuffled cards.
dealer=Hand()
player=Hand()
I don't really know how to post working code without posting a lot.
I
am not being too successful in trying to post enough code to have it
work without posting the entire code.
Here is the link if you want to run it.
http://www.codeskulptor.org/#user38_Kka7mh2v9u_9.py
The print out looks like this:
Hand contains H4 DQ.
I can (and am) currently printing the hand like this:
print Player's,player
print Dealer's,dealer
My question is can you add (self) in the __str__ so when you issue
the
command print player the player part is included in the __str__.
--
https://mail.python.org/mailman/listinfo/python-list
I think your main problem is a design issue.
I won't go into details, it would be too long but here's a way to fix your
problem:
# Untested code
class Player(object):
def __init__(self, name):
self.name = name
self.hand = Hand()
def __str__(self):
return '%s%s has %s' % (self.__class__.__name__, self.name, self.hand)
# A dealer is a special type of player
class Dealer(Player): pass
def deal():
global outcome, in_play,deck,dealer,player
# your code goes here
deck=Deck()
deck.shuffle()
print deck
players = [Dealer('Robert'), Player('John')]
for deal in range(2):
for player in players:
player.hand.add_card(deck.deal_card())
for player in players:
print str(player)
in_play = True
With the above design, the relation between player and its hand is implemented
with the Player attribute hand.
It's a classic design where the container knows about the content, but the
content does not know its container.
There are other solutions which do not require a new class, but I have the
feeling you will need the Player class in the future.
Moreover The design above I gave you will be probably broken in the future
when you add features to your code.
The same player may be a dealer or not, it may vary over time. You will
probably need a 'Table' object which handles a collection of players, with a
dealer, small blind, big blind etc, amount of money in the pot etc...
JM
-- IMPORTANT NOTICE:
The contents of this email and any attachments are confidential and may also
be privileged. If you are not the intended recipient, please notify the sender
immediately and do not disclose the contents to any other person, use it for
any purpose, or store or copy the information in any medium. Thank you.
Thanks for the tips
--
https://mail.python.org/mailman/listinfo/python-list
Re: Python handles globals badly.
On Thu, 04 Dec 2014 00:02:25 +0100, Skybuck Flying wrote: Mark Lawrence wrote in message news:mailman.16534.1417610132.18130.python-l...@python.org... On 03/12/2014 02:27, Skybuck Flying wrote: Excuse is: bad programming style. I don't need snot telling me how to program after 20 years of programming experience. This is so far the only thing pissing me off in python. Now I have to declare global in front of these variables every where I want to use em: Another example of a bad workman always blames his tools. Euhm, so why don't you program with just 0 and 1's then ? ;) Bye, Skybuck :) Because I DO know how to use my tools. -- God isn't dead. He just doesn't want to get involved. -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Fri, Dec 5, 2014 at 5:44 AM, Marko Rauhamaa ma...@pacujo.net wrote: Chris Angelico ros...@gmail.com: ... what you said There's no way to guarantee to keep calling the function. You have to depend on upstream. The caveats I listed are real concerns for the modern-day programmer. However, they are of a different nature than the complaint against time.monotonic(). But they're also reasons you can't have Python code around the problem. Anyway, it's only an issue for one platform, and only for some versions of it; basically, if you're targeting anything other than Windows XP, you should be able to use time.monotonic() without concerns. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Is Python installer/un-installer buggy on Windows?
On 12/4/2014 11:46 AM, Aseem Bansal wrote: Yeah, the problem seems to be with registry as every solution seems to be fiddling with registry. One can edit the registry directly with regedit. If you try it, follow the instruction to first make a backup. Look for a regedit tutorial on the web. I know that reinstalling OS is a really bad idea. But I have tried to find a way to solve this for months now. I have started a bounty on superuser also for the same in the question Python IDLE disappeared from the right click context menu. And asking on these groups was the last thing I can think of. I uninstalled via the Control Panel. I installed via the official Python installer for Windows. I also don't understand how a start menu entry can begin an installation but it is doing just that. To me, this specifically indicates a registry mixup. To prevent installation, delete or rename the downloaded install files. Now there seems to be 4 IDLE entries in my start menu. Two are valid (2.7.8, 3.4.2). The other two are previous installations of Python 3.4 that I did at different locations but removed later. Delete those two. I have stopped running IDLE from the start menu due to this. Because I am never sure whether it will re-install Python 3.4 at those old locations or not. Even right clicking those entries in start menu causes the installations to start. So I cannot even find the physical path of those entries. With Win7, I keep the two current installed Idles pinned to the taskbar. (I also have all three Python development versions pinned.) With 5 different builds of Idle to edit with, I open one or more first and then open to edit (often with Recent files). I almost never use 'Edit with Idle'. Maybe too much fiddling with the registry has caused it. Not sure about that. -- Terry Jan Reedy -- https://mail.python.org/mailman/listinfo/python-list
About Modifying Globals
Hi All,
I have a quick question regarding the modification of global variables within
functions. To illustrate, consider the following toy example:
a={1: set()}
b=9
def gt(l):
a[1] = a[1] | set([l])
When calling this last function and checking the a dictionary, I get:
gt(5)
a
{1: set([5])}
The set in the dictionary was modified. The question is, why isn't it necessary
to declare a as global within the gt function, as apposed to a case like
def gt2(l):
b=b+l
where I need to declare b as global within the function to avoid:
UnboundLocalError: local variable 'b' referenced before assignment.
I apologize if this question has been answered before.
Thank you.
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Re: About Modifying Globals
On Fri, Dec 5, 2014 at 7:09 AM, LJ luisjoseno...@gmail.com wrote: def gt(l): a[1] = a[1] | set([l]) def gt2(l): b=b+l These two may both look like they're assigning something, but one of them is assigning directly to the name b, while the other assigns to a subscripted element of a. In the first function, a is still the same object after the change; in the second, b has been replaced by a new object. That's why your second one needs a global declaration. It's all about names and assignment; if you're not assigning to the actual name, there's no need to declare where the name comes from, because you're only referencing it, not replacing it. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: About Modifying Globals
On Thu, Dec 4, 2014 at 1:09 PM, LJ luisjoseno...@gmail.com wrote:
Hi All,
I have a quick question regarding the modification of global variables
within functions. To illustrate, consider the following toy example:
a={1: set()}
b=9
def gt(l):
a[1] = a[1] | set([l])
When calling this last function and checking the a dictionary, I get:
gt(5)
a
{1: set([5])}
The set in the dictionary was modified. The question is, why isn't it
necessary to declare a as global within the gt function, as apposed to a
case like
def gt2(l):
b=b+l
where I need to declare b as global within the function to avoid:
UnboundLocalError: local variable 'b' referenced before assignment.
https://docs.python.org/3/faq/programming.html#what-are-the-rules-for-local-and-global-variables-in-python
In the first case, you never assign to a; you only modify it. Since it's
never assigned locally the compiler knows it can't be a local variable, so
it automatically makes it a global.
In the second case, the assignment to b causes the compiler to treat the
variable as local by default, so it needs to be explicitly marked as global.
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Re: time.monotonic() roll over
Ian Kelly ian.g.ke...@gmail.com writes: On Thu, Dec 4, 2014 at 11:09 AM, Marko Rauhamaa ma...@pacujo.net wrote: Chris Angelico ros...@gmail.com: It's not a Python issue. Python can't do anything more than ask the system, and if the system's value rolls over several times a year, Python can't magically cure that. The information has already been lost. Sure it could by having an invisible background thread occasionally call time.monotonic(). It could even be done on the side without a thread. Anyway, the idea of a clock is complicated: * the program could be stopped by a STOP signal * the program could be suspended from power management * the program could be resurrected from a virtual machine snapshot * the program could be migrated from a different physical machine This seems like a lot of effort to unreliably design around a problem that will matter to only a tiny fraction of users. - people's computers are mostly on batteries (laptops, tablets, smartphones) -- suspended from power management use case - corporations's computations are mostly virtualized -- possible ressurected, migrated use case i.e., the opposite might be true -- non-virtualized PCs connected to AC are (becoming) minority. -- Akira -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Fri, Dec 5, 2014 at 7:24 AM, Akira Li 4kir4...@gmail.com wrote: This seems like a lot of effort to unreliably design around a problem that will matter to only a tiny fraction of users. - people's computers are mostly on batteries (laptops, tablets, smartphones) -- suspended from power management use case - corporations's computations are mostly virtualized -- possible ressurected, migrated use case i.e., the opposite might be true -- non-virtualized PCs connected to AC are (becoming) minority. That's a massive over-simplification, of course, but given that my current desktop computer is running a dozen or so VMs for various purposes (usually not more than 3-4 concurrently), I can't disagree with you. However, there still are plenty of computers that are always either fully running, or fully shut down; just because people _can_ suspend with applications running doesn't mean they _will_. (Quite a few of my VMs, for instance, do not get saved/suspended - I shut them down whenever I'm done with them. Even when I do suspend a VM, I often terminate applications in it, and just use suspension to save having to boot the OS every time. But that's partly because those VMs are the ones running Windows for specific proprietary apps, and thus are coping with the vagaries of those apps.) In any case, it's not at all a problem to have the protection on systems that won't actually need it. Much better than lacking the protection on a system that does. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Urgent Need Sr. SDET (System) in Redmond, WA
Greetings My name is Amrish and I'm an IT Recruiter at Talented IT. Our records show that you are an experienced IT professional with experience relevant to one of my current contract openings. The job is located in Redmond, WA with one of our Fortune 100 client. They are looking for SR. SDET (System) and the following is a more detailed description of the job. Position Title: Sr. SDET (System) Location: Redmond, WA Duration: 6+months Position Requirements: * Strong C# or C++ or Java skills, ability to work independently to maintain and expand a test tools as part of a team supporting several projects * Experience writing code to test software on several platforms preferred (Windows, Android, etc..) with C++, C#, Java * Self-motivated, able to follow instructions and work with the team's priorities and decisions. * Strong test planning skills, able to come up with a robust test plan for a light weight UI application. * Ability to work independently to execute sign off (manual + automation) for the application. * Strong experience writing test automation in C#, MSTest, UIAutomation experience a plus * Experience writing test automation in C# or C++ * Self-start - willing and able to work independently with minimum supervision Additional Responsibilities: * Create, maintain and execute a set of test cases for all phases of the project * Create well written bugs and communicate issues/defects to the team * Validate new FW updates and all associated update scenarios * Launch and execute a host of test tools for product validation Thanks Warm Regards, Amrish B Technical Recruiter TalentedIT Inc amr...@talentedit.com 630-352-3306 800 W, Fifth Avenue, Suite 208A Naperville, IL - 60563 -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
Chris Angelico ros...@gmail.com: Even when I do suspend a VM, I often terminate applications in it, and just use suspension to save having to boot the OS every time. One interesting detail is DHCP leases. When it is resumed from suspension, a linux computer thinks it still has the old IP address, which might have already been granted to some other computer on the network. Thus, linux distros are equipped with hacky scripts that get executed soon after the machine is resumed (and before a lot of damage is done). One of them forces a DHCP renegotiation. A similar scheme is missing from virtual machines: a VM that wakes up from a snapshot doesn't automatically go through the resume scripts, even though it arguably should. Systemd probably shuffles the situation still more. Marko -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
On 04.12.2014 19:05, Chris Angelico wrote: With os.path it definitely is. With the actual code in question, it's a Python 2.7 project that mostly uses relative imports - inside package.module1 is import module2 etc - and I was writing an external script that calls on one of the modules. What ? I'm usually thinking Python 3 not 2 and I'm never sure which Python 2.x has backported which feature of 3, but I thought implicit relative imports like you seem to describe are not working in 2.7 ? Wolfgang -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
On Fri, Dec 5, 2014 at 7:56 AM, Wolfgang Maier wolfgang.ma...@biologie.uni-freiburg.de wrote: On 04.12.2014 19:05, Chris Angelico wrote: With os.path it definitely is. With the actual code in question, it's a Python 2.7 project that mostly uses relative imports - inside package.module1 is import module2 etc - and I was writing an external script that calls on one of the modules. What ? I'm usually thinking Python 3 not 2 and I'm never sure which Python 2.x has backported which feature of 3, but I thought implicit relative imports like you seem to describe are not working in 2.7 ? Hmm, I'm not sure, but certainly it does seem to work that way. Typing import foo from inside a package will import foo.py from the package directory. I haven't dug into the details of _why_, and if ever the project shifts to Python 3 (which I would like it to), we might have to change some of the import lines, but I'd still like to be able to reference foo.bar as meaning the bar top-level object in foo.py. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
On 04.12.2014 22:30, Chris Angelico wrote: On Fri, Dec 5, 2014 at 7:56 AM, Wolfgang Maier wolfgang.ma...@biologie.uni-freiburg.de wrote: On 04.12.2014 19:05, Chris Angelico wrote: With os.path it definitely is. With the actual code in question, it's a Python 2.7 project that mostly uses relative imports - inside package.module1 is import module2 etc - and I was writing an external script that calls on one of the modules. What ? I'm usually thinking Python 3 not 2 and I'm never sure which Python 2.x has backported which feature of 3, but I thought implicit relative imports like you seem to describe are not working in 2.7 ? Hmm, I'm not sure, but certainly it does seem to work that way. Typing import foo from inside a package will import foo.py from the package directory. I haven't dug into the details of _why_, and if ever the project shifts to Python 3 (which I would like it to), we might have to change some of the import lines, but I'd still like to be able to reference foo.bar as meaning the bar top-level object in foo.py. I checked what the docs say about this and it is totally confusing (at least me): https://docs.python.org/3/howto/pyporting.html#from-future-import-absolute-import says: from __future__ import absolute_import Implicit relative imports (e.g., importing spam.bacon from within spam.eggs with the statement import bacon) do not work in Python 3. This future statement moves away from that and allows the use of explicit relative imports (e.g., from . import bacon). In Python 2.5 you must use the __future__ statement to get to use explicit relative imports and prevent implicit ones. In Python 2.6 explicit relative imports are available without the statement, but you still want the __future__ statement to prevent implicit relative imports. In Python 2.7 the __future__ statement is not needed. In other words, unless you are only supporting Python 2.7 or a version earlier than Python 2.5, use this __future__ statement. which I read as there has been a stepwise transition between 2.5 and 2.7 so that 2.7 now behaves like Python 3 even without the __future__ statement. OTOH, I believe you, of course, if you're saying implicit relative imports are working just fine in 2.7, but then how to interpret the In Python 2.7 the __future__ statement is not needed. above ? Wolfgang -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Thu, Dec 4, 2014 at 1:24 PM, Akira Li 4kir4...@gmail.com wrote: Ian Kelly ian.g.ke...@gmail.com writes: This seems like a lot of effort to unreliably design around a problem that will matter to only a tiny fraction of users. - people's computers are mostly on batteries (laptops, tablets, smartphones) -- suspended from power management use case - corporations's computations are mostly virtualized -- possible ressurected, migrated use case i.e., the opposite might be true -- non-virtualized PCs connected to AC are (becoming) minority. By tiny fraction of users I was referring to people who a) work with Python 3.3+, b) use time.monotonic in their code, and c) possibly have said code running on versions of Windows older than Vista; not people who suspend their systems or use VMs. It's not clear to me whether those cases are relevant to the rollover concern anyway. I wouldn't be shocked if the GetTickCount() function simply stopped increasing while the system is suspended, since after all it's not ticking during that time. -- https://mail.python.org/mailman/listinfo/python-list
Re: Style question: Importing modules from packages - 'from' vs 'as'
On Fri, Dec 5, 2014 at 9:10 AM, Wolfgang Maier wolfgang.ma...@biologie.uni-freiburg.de wrote: which I read as there has been a stepwise transition between 2.5 and 2.7 so that 2.7 now behaves like Python 3 even without the __future__ statement. OTOH, I believe you, of course, if you're saying implicit relative imports are working just fine in 2.7, but then how to interpret the In Python 2.7 the __future__ statement is not needed. above ? Hmm. To be honest, I'm not sure. The Python 2.7 __future__ module claims that absolute_import became standard in 3.0, not 2.7, which seems to conflict with what you're seeing. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
Ian Kelly ian.g.ke...@gmail.com: It's not clear to me whether those cases are relevant to the rollover concern anyway. I wouldn't be shocked if the GetTickCount() function simply stopped increasing while the system is suspended, since after all it's not ticking during that time. So, what's the semantics of time.sleep(), select.select() et al wrt process or machine suspension? Marko -- https://mail.python.org/mailman/listinfo/python-list
RE: ORM opinion
First recommendation: Less layers. Instead of SQLAlchemy, just import sqlite3 and use it directly. You should be able to switch out import sqlite as db for import psycopg2 as db or any other Python DB API module, and still have most/all of the benefit of the extra layer, without any extra imports. Yeah, I am a fan of apsw but this is what I have now done. While I am fine with writing my own abstractions, its certainly less overhead using an orm. Secondly, see if you can keep the Python process running, instead of separately invoking it for every operation. This will mean some structural changes, but if you're specifying Python as the plugin interpreter (as opposed to, say, execute this program with these args, which is far more general), you can probably set up a wrapper script that calls on the user code repeatedly. Perhaps you could have a multiprocessing.Queue feeding tasks to the subprocess, via a little parent Python process. If you can't make those kinds of changes to the application, the next best would be a stubby driver process that feeds jobs to your real subprocess; the real work might be done by a Unix/TCP socket server, and the stub connects, feeds it some information, gets back a result, and disconnects. The stub will have an extremely minimal set of imports (the bear necessities of life, if you like), and the real process can import as much as it likes, because it won't be doing it for every operation. I am stuck with the current architecture, but the idea you propose has been thrown around, truth is I am not certain if we are enduring the effort of such a large rewrite that Python is the tool to use (this is a Windows application) but regardless your idea is one that is proposed. Thanks, jlc -- https://mail.python.org/mailman/listinfo/python-list
Re: ORM opinion
On 04/12/2014 23:20, Joseph L. Casale wrote: First recommendation: Less layers. Instead of SQLAlchemy, just import sqlite3 and use it directly. You should be able to switch out import sqlite as db for import psycopg2 as db or any other Python DB API module, and still have most/all of the benefit of the extra layer, without any extra imports. Yeah, I am a fan of apsw but this is what I have now done. While I am fine with writing my own abstractions, its certainly less overhead using an orm. Secondly, see if you can keep the Python process running, instead of separately invoking it for every operation. This will mean some structural changes, but if you're specifying Python as the plugin interpreter (as opposed to, say, execute this program with these args, which is far more general), you can probably set up a wrapper script that calls on the user code repeatedly. Perhaps you could have a multiprocessing.Queue feeding tasks to the subprocess, via a little parent Python process. If you can't make those kinds of changes to the application, the next best would be a stubby driver process that feeds jobs to your real subprocess; the real work might be done by a Unix/TCP socket server, and the stub connects, feeds it some information, gets back a result, and disconnects. The stub will have an extremely minimal set of imports (the bear necessities of life, if you like), and the real process can import as much as it likes, because it won't be doing it for every operation. I am stuck with the current architecture, but the idea you propose has been thrown around, truth is I am not certain if we are enduring the effort of such a large rewrite that Python is the tool to use (this is a Windows application) but regardless your idea is one that is proposed. Thanks, jlc Anything listed here http://www.pythoncentral.io/sqlalchemy-vs-orms/ you've not heard about? I found peewee easy to use although I've clearly no idea if it suits your needs. There's only one way to find out :) -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: Python docs disappointing
On Thu, Dec 4, 2014 at 6:27 PM, Albert van der Horst alb...@spenarnc.xs4all.nl wrote: In article mailman.16030.1416502295.18130.python-l...@python.org, Joel Goldstick joel.goldst...@gmail.com wrote: SNIP Plain google is far superior in finding information. And you tell me that writing yet another tutorial would improve that? No, there is just one way. The powers that be should look critically at their website, and test it with a beginners hat on. The community is in the best place to document language. And community is not limited to the official doc site. That includes outsiders doing their share of writing tutorials and whatnot. I don't find anything wrong about that. If you have problems with the docs, why not be a part of the solution? Write a doc for numpy and contribute it to the community. Man, I remember using MSDN 15 years ago when working with Visual Studio. And it's a paid product with docs. It's horrendous. I'm trying to wrap my mind around DOCUMENTION being STUPID. -- Joel Goldstick http://joelgoldstick.com Groetjes Albert -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spearc.xs4all.nl =n http://home.hccnet.nl/a.w.m.van.der.horst -- https://mail.python.org/mailman/listinfo/python-list -- Freelance Grails http://grails.asia/ and Java http://javadevnotes.com/ developer -- https://mail.python.org/mailman/listinfo/python-list
Re: ORM opinion
On Fri, Dec 5, 2014 at 10:20 AM, Joseph L. Casale jcas...@activenetwerx.com wrote: I am stuck with the current architecture, but the idea you propose has been thrown around, truth is I am not certain if we are enduring the effort of such a large rewrite that Python is the tool to use (this is a Windows application) but regardless your idea is one that is proposed. Windows? Then even more important to minimize the number of processes you create. They're very costly on Windows. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
RE: ORM opinion
Anything listed here http://www.pythoncentral.io/sqlalchemy-vs-orms/ you've not heard about? I found peewee easy to use although I've clearly no idea if it suits your needs. There's only one way to find out :) Hi Mark, I found that article before posting and some of the guys here have already started using peewee. I don't have much time with it yet. So far all I can say is its unfortunate some package authors take such an approach to naming. I can't fathom sitting across the table from a CTO and CFO who are authorizing a 7 figure expenditure and then telling them about my peewee app with its playhouse module? Sigh... That aside, compared to all the rest it seems to fit the requirements. jlc -- https://mail.python.org/mailman/listinfo/python-list
Re: ORM opinion
On Fri, Dec 5, 2014 at 10:43 AM, Joseph L. Casale jcas...@activenetwerx.com wrote: I found that article before posting and some of the guys here have already started using peewee. I don't have much time with it yet. So far all I can say is its unfortunate some package authors take such an approach to naming. I can't fathom sitting across the table from a CTO and CFO who are authorizing a 7 figure expenditure and then telling them about my peewee app with its playhouse module? Sigh... Then never EVER get into Ruby. That seems to be the norm for gem naming. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: About Modifying Globals
On 12/04/2014 03:09 PM, LJ wrote:
Hi All,
I have a quick question regarding the modification of global variables within
functions. To illustrate, consider the following toy example:
a={1: set()}
b=9
def gt(l):
a[1] = a[1] | set([l])
When calling this last function and checking the a dictionary, I get:
gt(5)
a
{1: set([5])}
The set in the dictionary was modified. The question is, why isn't it necessary
to declare a as global within the gt function, as apposed to a case like
def gt2(l):
b=b+l
where I need to declare b as global within the function to avoid:
UnboundLocalError: local variable 'b' referenced before assignment.
The reason this sort of thing seems to confuse lots of people is that we
insist on calling these things assignments. The thing that's global is
the name 'a'. It's global because it's in the global() namespace of
some module.
The data that's assigned to it is an object. You bind the object to
the name 'a' with an assignment statement. If that object is immutable,
then the only way to change 'a' is to do another assignment.
But if the object is mutable, as a set is, then it can change as much as
you like without rebinding the name.
A given object may have any number of names bound to it, including no
names. An example of that could be objects that are referenced only in
some list.
Python doesn't have declarations, so when a function is compiled, the
compiler has to infer what names are to be local and what are not. The
rule it normally uses is roughly based on whether an assignment occurs
somewhere inside the function.
--
DaveA
--
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Re: Python docs disappointing
On 12/04/2014 03:27 AM, Albert van der Horst wrote: That doesn't help. I'm a very experienced programmer and work in routinely a dozen languages. Sometimes I do python. I want to do numeric work. I remember the name numpy. It is important, everybody knows it, it is all over the place. So I want to find its docs, or some lead, whatever. I go to the official Python site, http://docs.python.org and type in numpy in the search machine. It is embarassing, try it! That would indeed be embarrassing if numpy was a part of Python or had anything to do with the python.org project. In fact it doesn't. It's a third-party library for use with python. As a beginner I would type in numpy to google and see what happens. Would you expect to go to Microsoft MSDN to find information on a third-party library, such as, say, SDL or Allegro, that you use in Visual Studio? Plain google is far superior in finding information. Of course, since the information you are looking is third-party to python.org for a start. And you tell me that writing yet another tutorial would improve that? No, there is just one way. The powers that be should look critically at their website, and test it with a beginners hat on. Your ire is misplaced. The GP was saying that if there is a deficiency in the Python docs you can help fix that. If there's a deficiency in the numpy docs, you can ask them about fixing that's what he means. -- https://mail.python.org/mailman/listinfo/python-list
Re: About Modifying Globals
On Fri, Dec 5, 2014 at 10:54 AM, Dave Angel da...@davea.name wrote: Python doesn't have declarations, so when a function is compiled, the compiler has to infer what names are to be local and what are not. The rule it normally uses is roughly based on whether an assignment occurs somewhere inside the function. Not strictly true; Python just inverts the C model. In C, you declare your locals; in Python, you declare your globals. The global x statement is a declaration. But otherwise, yes. When a function is compiled, the compiler has to figure out what's local and what's global. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
Marko Rauhamaa wrote: So, if I call time.sleep(86400) and the program is suspended for 24 hours, should time.sleep() return right after it is resumed or after another 24 hours? If the program is suspended, then no time should pass for that program. Since sleep() is given in terms of a duration, not an absolute time (sleep until now + 24 hours), if no time passes for that program, sleep() should sleep for 24 hours *after the program resumes*. Unfortunately a lot of systems get that wrong. E.g. I just ran sleep 30 from my Linux shell, immediately paused it using Ctrl-Z, waited a couple of minutes, and used fg to continue. It returned immediately. Why is this behaviour wrong? Consider why people might call sleep. They're normally calling it to wait for something else to complete. Often that something else is an external process (wait a few seconds to let the hard drive finish syncing, wait for the web server to get less busy, wait for the user to catch up...) but it might be another thread in the same process. If the process is suspended, that other thread won't get to run, and so even though time on the outside has continued to move forward, from the perspective of the process, it hasn't. The same applies even more so if the process is running in a virtual machine which has just been suspended. The same applies if the system clock is adjusted mid-sleep. If I call sleep 60, then immediately adjust the clock forward an hour (say, due to a daylight savings adjustment), that shouldn't cause sleep to return. It should still suspend for 60 seconds. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On Thu, 04 Dec 2014 16:25:44 +0100, ast wrote: There is no roll over problem with time.time() since the very first one in planned far in the future, but time.time() can go backward when a date update throught NTP server is done. time.monotonic() is monotonic but roll over often (every 49.7 days) So what to do ? Using time.monotonic() and take some actions if a roll over is detected ? One possibility: use both and monitor the skew (the difference between the two clocks). The first time you read them, calculate and store the epoch for time.monotic(). On subsequent calls, repeat the calculation and check that the epoch is approximately the same. If it isn't, the difference between the actual and expected values should be close to an exact multiple of 2**32 milliseconds, which tells you how many times time.monotonic() has rolled over. Adjustments to the clock on which time.time() is based shouldn't exceed a few seconds per year, so there's not much risk that you won't be able to figure out the correct adjustment. -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On 12/04/2014 07:39 PM, Steven D'Aprano wrote: Marko Rauhamaa wrote: So, if I call time.sleep(86400) and the program is suspended for 24 hours, should time.sleep() return right after it is resumed or after another 24 hours? If the program is suspended, then no time should pass for that program. Since sleep() is given in terms of a duration, not an absolute time (sleep until now + 24 hours), if no time passes for that program, sleep() should sleep for 24 hours *after the program resumes*. Unfortunately a lot of systems get that wrong. E.g. I just ran sleep 30 from my Linux shell, immediately paused it using Ctrl-Z, waited a couple of minutes, and used fg to continue. It returned immediately. Why is this behaviour wrong? Consider why people might call sleep. They're normally calling it to wait for something else to complete. Often that something else is an external process (wait a few seconds to let the hard drive finish syncing, wait for the web server to get less busy, wait for the user to catch up...) but it might be another thread in the same process. If the process is suspended, that other thread won't get to run, and so even though time on the outside has continued to move forward, from the perspective of the process, it hasn't. The same applies even more so if the process is running in a virtual machine which has just been suspended. The same applies if the system clock is adjusted mid-sleep. If I call sleep 60, then immediately adjust the clock forward an hour (say, due to a daylight savings adjustment), that shouldn't cause sleep to return. It should still suspend for 60 seconds. And I say you have it exactly backwards. People should NOT call sleep() to measure something, they should only call it to release the processor for up to a specified time. That time should normally be a major fraction of the time that some external event is expected to take. Then the code should check the external event and sleep some more if necessary. If efficiency were not an issue, the code would just do a busy loop, checking the external condition repeatedly. Since the OS has no way of knowing whether the thing being waited for is a thread, another process, a human being, a network operation, or the end of the world, the interpretation of sleep needs to be the most conservative one. There are many ways of suspending a process, and some of them will also suspend the external event. Since the OS cannot know which case is significant, it has to return control to the caller at the soonest of the many possible interpretations. -- DaveA -- https://mail.python.org/mailman/listinfo/python-list
Re: About Modifying Globals
LJ wrote:
Hi All,
I have a quick question regarding the modification of global variables
within functions. To illustrate, consider the following toy example:
a={1: set()}
b=9
def gt(l):
a[1] = a[1] | set([l])
The difference between this example and your second one:
def gt2(l):
b=b+l
is that the second is a binding operation and the first is not.
Binding operations include direct assignment to a name, deletions, imports
and a few other things:
b = 23
del b
import sys as b
are all considered binding operations, since they bind a value to a name
(or, in the case of del, unbind it). Inside functions, the compiler follows
the rule that any binding operation makes that variable a local for the
entire function, unless declared global.
So in the gt2() example, b = b + 1 is interpreted as this:
- look up local variable b;
- add one to the result;
- assign it to local variable b.
which fails because b hasn't got a value yet.
This is different from, say, Lua, where that line would be interpreted as:
- look up local variable b;
- if that doesn't exist, look up global variable b instead;
- add one to the result;
- assign it to local variable b.
But that's not what Python does.
On the other hand, your first example doesn't include a direct assignment to
a name:
a[1] = a[1] | set([l])
looks like an assignment, but it's actually a method call! That is
approximately equivalent to:
a.__setitem__(1, X)
with X equal to the right hand side. Since that's a method call, it doesn't
count as a binding operation and the compiler doesn't treat a as a local,
it treats it as global, so the lookup on the right hand side succeeds, and
the method call modifies the set in place.
--
Steven
--
https://mail.python.org/mailman/listinfo/python-list
Re: About Modifying Globals
On 12/04, LJ wrote:
Hi All,
I have a quick question regarding the modification of global variables within
functions. To illustrate, consider the following toy example:
a={1: set()}
b=9
def gt(l):
a[1] = a[1] | set([l])
When calling this last function and checking the a dictionary, I get:
gt(5)
a
{1: set([5])}
The set in the dictionary was modified. The question is, why isn't it
necessary to declare a as global within the gt function, as apposed to a case
like
def gt2(l):
b=b+l
where I need to declare b as global within the function to avoid:
UnboundLocalError: local variable 'b' referenced before assignment.
Well. To understand the difference, one first has to know the mechanism of
CPython.
When you have a script, CPython will first parse it, and then generate bytecode
representation, and then finally execute it.
If you take a look at the bytecode of both your source code, you will notice,
that.
In the first snippet, there is something like LOAD_NAME, which loads the global
name a.
However, in the second snippet, there would be a LOAD_FAST, which loads the
local name b (which is, technically speaking, stored in the PyFrameObj).
The reason Python treats it differently, is, IIUC, for better semantic meaning,
and also, for huge performance improvement.
Hope that explains.
Regards.
--
Shiyao Ma
http://introo.me
--
https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
Dave Angel wrote: On 12/04/2014 07:39 PM, Steven D'Aprano wrote: Marko Rauhamaa wrote: So, if I call time.sleep(86400) and the program is suspended for 24 hours, should time.sleep() return right after it is resumed or after another 24 hours? If the program is suspended, then no time should pass for that program. Since sleep() is given in terms of a duration, not an absolute time (sleep until now + 24 hours), if no time passes for that program, sleep() should sleep for 24 hours *after the program resumes*. Unfortunately a lot of systems get that wrong. E.g. I just ran sleep 30 from my Linux shell, immediately paused it using Ctrl-Z, waited a couple of minutes, and used fg to continue. It returned immediately. Why is this behaviour wrong? Consider why people might call sleep. They're normally calling it to wait for something else to complete. Often that something else is an external process (wait a few seconds to let the hard drive finish syncing, wait for the web server to get less busy, wait for the user to catch up...) but it might be another thread in the same process. If the process is suspended, that other thread won't get to run, and so even though time on the outside has continued to move forward, from the perspective of the process, it hasn't. The same applies even more so if the process is running in a virtual machine which has just been suspended. The same applies if the system clock is adjusted mid-sleep. If I call sleep 60, then immediately adjust the clock forward an hour (say, due to a daylight savings adjustment), that shouldn't cause sleep to return. It should still suspend for 60 seconds. And I say you have it exactly backwards. People should NOT call sleep() to measure something, I never suggested you call sleep to measure something. You call sleep to *wait* for something. I even used the word wait four times in the above. they should only call it to release the processor for up to a specified time. That's silly. Zero is up to any positive value you want. Do you really intend to say that this would be an acceptable implementation of sleep()? def sleep(delay): return That time should normally be a major fraction of the time that some external event is expected to take. Then the code should check the external event and sleep some more if necessary. If efficiency were not an issue, the code would just do a busy loop, checking the external condition repeatedly. In many cases, you don't have an external condition that can be easily or practically checked. So you estimate how long you need to wait, add a safety margin, and write sleep 5 (for some value of 5), and hope. If you are a sys admin writing a script that runs during boot time, you do that a lot. Or at least the ones I work with do :-) Since the OS has no way of knowing whether the thing being waited for is a thread, another process, a human being, a network operation, or the end of the world, the interpretation of sleep needs to be the most conservative one. I agree! And returning immediately is not the most conservative one. The most conservative approach is to assume that while you're suspended, *everything else* is suspended too, so when you resume you still have to sleep for the full N seconds. There are many ways of suspending a process, and some of them will also suspend the external event. Since the OS cannot know which case is significant, it has to return control to the caller at the soonest of the many possible interpretations. /s/latest/ -- Steven -- https://mail.python.org/mailman/listinfo/python-list
help with processing text file
Hi, Given the sample text file below (where the gibberish represent the irrelevant portions) : abcddsdfffgfg ggfhghghgfhghgh round 5 xccdcxcfd sdfdffdfbcvcvbbvnghg score = 0.4533 abcddsdfffgfg round 5 level = 0.15 ggfhghghgfhghgh round 10 dfsdfdcdsd sdfdffdfbcvcvbbvnghg score = 0.4213 sdsdaawsdsround 10 level = 0.13 ..and so on I would like to extract the values for round, score and level: 5 0.4533 0.15 10 0.4213 0.13 and so on... Please advise me how it can be done, and what Python functions are useful. Thanks. -- https://mail.python.org/mailman/listinfo/python-list
Re: help with processing text file
On 12/04/2014 08:46 PM, C. Ng wrote: Hi, Given the sample text file below (where the gibberish represent the irrelevant portions) : abcddsdfffgfg ggfhghghgfhghgh round 5 xccdcxcfd sdfdffdfbcvcvbbvnghg score = 0.4533 abcddsdfffgfg round 5 level = 0.15 ggfhghghgfhghgh round 10 dfsdfdcdsd sdfdffdfbcvcvbbvnghg score = 0.4213 sdsdaawsdsround 10 level = 0.13 ..and so on I would like to extract the values for round, score and level: 5 0.4533 0.15 10 0.4213 0.13 and so on... Please advise me how it can be done, and what Python functions are useful. Thanks. I would use regular expressions. See https://docs.python.org/3/library/re.html Gary Herron -- https://mail.python.org/mailman/listinfo/python-list
Re: Python handles globals badly.
On Dec 4, 2014, at 8:56 PM, Dennis Lee Bieber wlfr...@ix.netcom.com wrote: On Thu, 04 Dec 2014 14:51:14 +0200, Marko Rauhamaa ma...@pacujo.net declaimed the following: Chris Angelico ros...@gmail.com: A lot of programs don't use threads, and therefore cannot have thread safety problems - or, looking at it the other way, do not care about thread safetiness. It's like having Neil Armstrong wear water wings to make sure he won't drown in the Sea of Tranquility. The water wings would be too unwieldy since they'd have to be six times as large on the moon. It's all about risk/benefit analysis. Actually, since the pull of gravity is 1/6th that of earth, but the density of the water is the Sea is the same, the water wings should be smaller to provide the same degree of lift. Of course, the lack of atmospheric pressure is going to result in the water wings expanding, perhaps to the bursting point... -- Wulfraed Dennis Lee Bieber AF6VN wlfr...@ix.netcom.comHTTP://wlfraed.home.netcom.com/ -- https://mail.python.org/mailman/listinfo/python-list Wrong, again I’m afraid. Assume for a moment you are under a dome pressurized to one standard atmosphere in some future moon colony and are in a swimming pool. Both you AND the water are under 1/6th as much gravitational pull. Neither your density nor the water’s density has changed. Density is a function of the atomic weight of the elements making up both you and the water and the inter-atomic/molecular spacing of those elements. Neither has changed. Therefore the volume of buoyant material (in the case of water wings, air) necessary to keep you above water is the same on earth as it would be on the moon. -Bill -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
On 12/04/2014 09:54 PM, Steven D'Aprano wrote: Dave Angel wrote: On 12/04/2014 07:39 PM, Steven D'Aprano wrote: Marko Rauhamaa wrote: So, if I call time.sleep(86400) and the program is suspended for 24 hours, should time.sleep() return right after it is resumed or after another 24 hours? If the program is suspended, then no time should pass for that program. Since sleep() is given in terms of a duration, not an absolute time (sleep until now + 24 hours), if no time passes for that program, sleep() should sleep for 24 hours *after the program resumes*. Unfortunately a lot of systems get that wrong. E.g. I just ran sleep 30 from my Linux shell, immediately paused it using Ctrl-Z, waited a couple of minutes, and used fg to continue. It returned immediately. Why is this behaviour wrong? Consider why people might call sleep. They're normally calling it to wait for something else to complete. Often that something else is an external process (wait a few seconds to let the hard drive finish syncing, wait for the web server to get less busy, wait for the user to catch up...) but it might be another thread in the same process. If the process is suspended, that other thread won't get to run, and so even though time on the outside has continued to move forward, from the perspective of the process, it hasn't. The same applies even more so if the process is running in a virtual machine which has just been suspended. The same applies if the system clock is adjusted mid-sleep. If I call sleep 60, then immediately adjust the clock forward an hour (say, due to a daylight savings adjustment), that shouldn't cause sleep to return. It should still suspend for 60 seconds. And I say you have it exactly backwards. People should NOT call sleep() to measure something, I never suggested you call sleep to measure something. You call sleep to *wait* for something. I even used the word wait four times in the above. I mentioned measurement because I couldn't imagine any other reason you would be arguing the other side. You're certainly not waiting for the event, wleep has no parameters that let you specify what event you might be waiting for. they should only call it to release the processor for up to a specified time. That's silly. Zero is up to any positive value you want. Do you really intend to say that this would be an acceptable implementation of sleep()? def sleep(delay): return Yes, of course. Not very machine efficient, but perfectly correct. Because the testing code will make its check, and turn right around and issue another sleep call. This is called a busy loop, and I mention it below. It is the degenerate (if inefficient) form. That time should normally be a major fraction of the time that some external event is expected to take. Then the code should check the external event and sleep some more if necessary. If efficiency were not an issue, the code would just do a busy loop, checking the external condition repeatedly. In many cases, you don't have an external condition that can be easily or practically checked. So you estimate how long you need to wait, add a safety margin, and write sleep 5 (for some value of 5), and hope. If you are a sys admin writing a script that runs during boot time, you do that a lot. Or at least the ones I work with do :-) Since the OS has no way of knowing whether the thing being waited for is a thread, another process, a human being, a network operation, or the end of the world, the interpretation of sleep needs to be the most conservative one. I agree! And returning immediately is not the most conservative one. The most conservative approach is to assume that while you're suspended, *everything else* is suspended too, so when you resume you still have to sleep for the full N seconds. There are many ways of suspending a process, and some of them will also suspend the external event. Since the OS cannot know which case is significant, it has to return control to the caller at the soonest of the many possible interpretations. /s/latest/ I guess we'll just have to agree to disagree. I can now see the usefulness of a function like you describe, I just can't imagine it being the sleep() we've all come to know and love. -- DaveA -- https://mail.python.org/mailman/listinfo/python-list
The binding operator, and what gets bound to what (was: About Modifying Globals)
Steven D'Aprano steve+comp.lang.pyt...@pearwood.info writes: LJ wrote: def gt(l): a[1] = a[1] | set([l]) The difference between this example and your second one: def gt2(l): b=b+l is that the second is a binding operation and the first is not. I disagree; they're both binding operations (and they both use the binding operator ‘=’ to express this). The difference between the two is: what reference is being bound? * In the first example, the reference is ‘a[1]’. That reference is re-bound to a different object; whatever object it was previously bound to is forgotten. * In the second example, the reference is ‘b’. That reference is re-bound to a different object; whatever object it was previously bound to is forgotten. So, both of them bind (or re-bind) a reference to an object. The only difference between the operations is the parameters. -- \ “People always ask me, ‘Where were you when Kennedy was shot?’ | `\Well, I don't have an alibi.” —Emo Philips | _o__) | Ben Finney -- https://mail.python.org/mailman/listinfo/python-list
Re: help with processing text file
On 12/04/2014 11:46 PM, C. Ng wrote: Hi, Given the sample text file below (where the gibberish represent the irrelevant portions) : abcddsdfffgfg ggfhghghgfhghgh round 5 xccdcxcfd sdfdffdfbcvcvbbvnghg score = 0.4533 abcddsdfffgfg round 5 level = 0.15 ggfhghghgfhghgh round 10 dfsdfdcdsd sdfdffdfbcvcvbbvnghg score = 0.4213 sdsdaawsdsround 10 level = 0.13 ..and so on I would like to extract the values for round, score and level: 5 0.4533 0.15 10 0.4213 0.13 and so on... Please advise me how it can be done, and what Python functions are useful. There's lots of ambiguity in that specification. Can you be sure, for example that the gibberish does not ever include the string round, score, or level? Can you be sure that the relevant 3 lines for a given record are adjacent, and in that order? Do you happen to know that round always starts in a particular column?, and that score starts in another particular column? How would you solve it by hand? Something like the following? OPen the file. Skip all lines till column 19-23 contain round find the first space delimited field starting in column 25, and call it round_num On the next line, split the line into words, and save the last word into score_val On the next line, take a substring of the line starting with column 23, parse it into words, and store the second word in level_num Save the values round_num,score_val, and level_num in a tuple, or a string, or whatever you find useful, and append it to a result list. Repeat till end of file. Lots more error checking is possible, and advisable, but without knowing what the file really looks like, I see no point in guessing. -- DaveA -- https://mail.python.org/mailman/listinfo/python-list
Re: time.monotonic() roll over
Steven D'Aprano steve+comp.lang.pyt...@pearwood.info: Unfortunately a lot of systems get that wrong. E.g. I just ran sleep 30 from my Linux shell, immediately paused it using Ctrl-Z, waited a couple of minutes, and used fg to continue. It returned immediately. Why is this behaviour wrong? I think the #1 thing is to specify the behavior clearly. I'm not seeing that so it is impossible to say if the GNU coreutils sleep or time.sleep() does what it was designed to do. I must admit I have neglected to document that situation in some of my related designs. Also, I think what is right or wrong depends on the use case. Ideally, there are facilities to implement the desired semantics. If a program spends long periods in an induced coma (which is becoming more and more common nowadays), the whole design of the program is under quite a bit of strain. What to do with time-based statistics collection? Should periodic operations catch up with the lost time by repeating in a tight loop for a zillion times? What to do with impossible, out-of-order event sequences? Marko -- https://mail.python.org/mailman/listinfo/python-list
dict turn to list at runtime unexpected!!!
Why the following code gives me errors??? And why the print statement run 2
times? I'll be appreciated your helps, thanks,
addrnum_dict = {'a':1,'b':2}
def orderaddrtimes():
global addrnum_dict
print type(addrnum_dict)
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1], reverse
= True)
#addrnum_dict = OrderedDict(sorted(addrnum_dict.items(), key=lambda t:
t[0]))
if __name__ == '__main__':
kinds = [a,b]
for tmp_kind in kinds:
orderaddrtimes()
##
errors:
python aaa.py
type 'dict'
type 'list'
Traceback (most recent call last):
File aaa.py, line 16, in module
orderaddrtimes()
File aaa.py, line 11, in orderaddrtimes
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1], reverse
= True)
AttributeError: 'list' object has no attribute 'iteritems'
--
https://mail.python.org/mailman/listinfo/python-list
dict turn to list unexpected at runtime???
Why the following code gives me errors??? And why the print statement run 2
times? I'll be appreciated your helps, thanks,
addrnum_dict = {'a':1,'b':2}
def orderaddrtimes():
global addrnum_dict
print type(addrnum_dict)
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1], reverse
= True)
#addrnum_dict = OrderedDict(sorted(addrnum_dict.items(), key=lambda t:
t[0]))
if __name__ == '__main__':
kinds = [a,b]
for tmp_kind in kinds:
orderaddrtimes()
##
errors:
python aaa.py
type 'dict'
type 'list'
Traceback (most recent call last):
File aaa.py, line 16, in module
orderaddrtimes()
File aaa.py, line 11, in orderaddrtimes
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1], reverse
= True)
AttributeError: 'list' object has no attribute 'iteritems'
--
https://mail.python.org/mailman/listinfo/python-list
Re: dict turn to list unexpected at runtime???
On 05Dec2014 15:01, telnetgm...@gmail.com telnetgm...@gmail.com wrote:
Why the following code gives me errors??? And why the print statement run 2
times? I'll be appreciated your helps, thanks,
addrnum_dict = {'a':1,'b':2}
def orderaddrtimes():
global addrnum_dict
print type(addrnum_dict)
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1], reverse =
True)
Because of the line above. The return value of sorted() is a list. You assign
that list to addrnum_dict. That name now refers to the list from sorted().
Because you call the orderaddrtimes() function twice, the second time you call
it addrnum_dict is the list from the first call. Not a dict.
You would be best to not assign the result of sorte() to addrnum_dict.
Assign it to something else.
#addrnum_dict = OrderedDict(sorted(addrnum_dict.items(), key=lambda t: t[0]))
if __name__ == '__main__':
kinds = [a,b]
for tmp_kind in kinds:
orderaddrtimes()
##
errors:
python aaa.py
type 'dict'
type 'list'
Traceback (most recent call last):
File aaa.py, line 16, in module
orderaddrtimes()
File aaa.py, line 11, in orderaddrtimes
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1], reverse =
True)
AttributeError: 'list' object has no attribute 'iteritems'
Thank you for including the complete error output. This is very helpful, and
often essential.
Cheers,
Cameron Simpson c...@zip.com.au
Who are all you people and why are you in my computer? - Kibo
--
https://mail.python.org/mailman/listinfo/python-list
Re: dict turn to list unexpected at runtime???
On Fri, 05 Dec 2014 15:01:51 +0800, telnetgm...@gmail.com wrote:
Why the following code gives me errors??? And why the print statement run 2
times? ...
addrnum_dict = {'a':1,'b':2}
def orderaddrtimes():
global addrnum_dict
print type(addrnum_dict)
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1],
reverse = True)
#addrnum_dict = OrderedDict(sorted(addrnum_dict.items(), key=lambda t:
t[0]))
if __name__ == '__main__':
kinds = [a,b]
for tmp_kind in kinds:
orderaddrtimes()
The print statement runs twice because you're calling orderaddrtimes
twice, once for a and once for b.
addrnum_dict becomes a list when you bind it to the return value from
sorted on the first call to orderaddrtimes; you get the error on the
second call.
HTH,
Dan
--
https://mail.python.org/mailman/listinfo/python-list
Re: Do you like the current design of python.org?
Peter Otten __pete...@web.de writes: Did you ever hit the Socialize button? No. Are you eager to see the latest tweets when you are reading a PEP? No. Do you run away screaming from a page where nothing moves without you hitting a button? No, I like pages where I am in control. Do you appreciate the choice between ten or so links to the documentation? Maybe, I have bookmarked my route to the documentation - and usually do not see the choices. But, when I need to update my bookmark, I might like the choices. ... PS: Is there a twitter.com something that I can block to trade black friday and cyber monkey sales for a box with a good old error message? I have used a firewall to reject connections to intrusive sites (like facebook and Google). Under Linux, I used lsof -i to find out to which sites connections are made without my knowledge. I then used http://www.heise.de/netze/tools/whois/; to find out to which organisations those sites belong and banned them with firewall rules when those connections did not seem to satisfy a justified aim. -- https://mail.python.org/mailman/listinfo/python-list
Re: dict turn to list unexpected at runtime???
On Friday, December 5, 2014 3:20:14 PM UTC+8, Cameron Simpson wrote:
On 05Dec2014 15:01, telnetgm...@gmail.com telnetgm...@gmail.com wrote:
Why the following code gives me errors??? And why the print statement run 2
times? I'll be appreciated your helps, thanks,
addrnum_dict = {'a':1,'b':2}
def orderaddrtimes():
global addrnum_dict
print type(addrnum_dict)
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1],
reverse = True)
Because of the line above. The return value of sorted() is a list. You
assign
that list to addrnum_dict. That name now refers to the list from sorted().
Because you call the orderaddrtimes() function twice, the second time you
call
it addrnum_dict is the list from the first call. Not a dict.
You would be best to not assign the result of sorte() to addrnum_dict.
Assign it to something else.
#addrnum_dict = OrderedDict(sorted(addrnum_dict.items(), key=lambda t:
t[0]))
if __name__ == '__main__':
kinds = [a,b]
for tmp_kind in kinds:
orderaddrtimes()
##
errors:
python aaa.py
type 'dict'
type 'list'
Traceback (most recent call last):
File aaa.py, line 16, in module
orderaddrtimes()
File aaa.py, line 11, in orderaddrtimes
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1],
reverse = True)
AttributeError: 'list' object has no attribute 'iteritems'
Thank you for including the complete error output. This is very helpful, and
often essential.
Cheers,
Cameron Simpson c...@zip.com.au
Who are all you people and why are you in my computer? - Kibo
Thanks for your help!
I admit I have poor experience on python, and I careless also.
Thanks!
--
https://mail.python.org/mailman/listinfo/python-list
Re: dict turn to list at runtime unexpected!!!
On Friday, December 5, 2014 2:56:50 PM UTC+8, telne...@gmail.com wrote:
Why the following code gives me errors??? And why the print statement run 2
times? I'll be appreciated your helps, thanks,
addrnum_dict = {'a':1,'b':2}
def orderaddrtimes():
global addrnum_dict
print type(addrnum_dict)
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1],
reverse = True)
#addrnum_dict = OrderedDict(sorted(addrnum_dict.items(), key=lambda t:
t[0]))
if __name__ == '__main__':
kinds = [a,b]
for tmp_kind in kinds:
orderaddrtimes()
##
errors:
python aaa.py
type 'dict'
type 'list'
Traceback (most recent call last):
File aaa.py, line 16, in module
orderaddrtimes()
File aaa.py, line 11, in orderaddrtimes
addrnum_dict = sorted(addrnum_dict.iteritems(), key=lambda d:d[1],
reverse = True)
AttributeError: 'list' object has no attribute 'iteritems'
https://groups.google.com/forum/#!topic/comp.lang.python/eY7jecLLO48
this man helped me find out the problem.
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https://mail.python.org/mailman/listinfo/python-list
