Re: Why is it different about '\s' Matches whitespace and Equivalent to [\t\n\r\f]?

On Thursday, July 10, 2014 7:18:01 AM UTC-4, MRAB wrote: On 2014-07-10 11:05, r...@gmail.com wrote: It's equivalent to [ \t\n\r\f], i.e. it also includes a space, so either the tutorial is wrong, or you didn't look closely enough. :-) The string starts with ' ', not '\t'.

What does (A ``quote'' is the character used to open the string, i.e. either ' or .) mean?

Hi, For me, it is difficult to understand the last line of the paragraph below in parenthesis (A ``quote'' is the character used to open the string, i.e. either ' or .) It talks about triple-quoted strings. Where is ``quote'' from? It has two ` and '. What this different ` and ' do for here?

Re: What does (A ``quote'' is the character used to open the string, i.e. either ' or .) mean?

On Thursday, July 10, 2014 10:14:14 AM UTC-4, Chris Kwpolska Warrick wrote: Please don't learn from this link. It's from 2001. You should learn from modern documentation: https://docs.python.org/ (if not running 3.4.x, change the version in the top) You also should not read

How to decipher :re.split(r(\(\([^)]+\)\)) in the example

Hi, This example is from the link: https://wiki.python.org/moin/RegularExpression I have thought about it quite a while without a clue yet. I notice that it uses double quote , in contrast to ' which I see more often until now. It looks very complicated to me. Could you simplified it to a

I am confused about ' and

Hi, It is still in the Regular expression operations concept, this link: has example using single quote mark: ' https://docs.python.org/2/library/re.html#re.split While in this link: https://docs.python.org/3/howto/regex.html It gives table with quote: Regular String Raw string ab*

How to extract digit from a number?

Hi, I see the following example on line, but it does not work. I do not know what is wrong. Could you correct it for me? Thanks, I'm not sure what [1, 1, 0, 0, 0, 0, ...] has to do with 128, but if you want the base 10 digits: a = 1234 [int(d) for d in str(a)]

Re: How to extract digit from a number?

On Monday, July 21, 2014 4:26:25 PM UTC-4, Tim Chase wrote: On 2014-07-21 13:14, fl wrote: You don't specify *what* is wrong or what constitutes does not work. If you provide an example of what you *do* want, folks here can help you get closer to the code you need to do what you intend

How to use string constant?

Hi, I learn string constant on Python tutorial at: https://docs.python.org/2/library/string.html Although it gives explanation, it does not show me any example usage. Could you give me an example on using these options? string.digits string.ascii_letters Thanks, --

Question about Pass-by-object-reference?

Hi, I learn Python function call on tutorial. There is a link on this subject. http://robertheaton.com/2014/02/09/pythons-pass-by-object-reference-as-explained-by-philip-k-dick/ Although it explains clearly, the figure makes me puzzled. Python is different. As we know, in Python, Object

Re: Question about Pass-by-object-reference?

On Tuesday, July 22, 2014 3:04:09 PM UTC-4, fl wrote: Hi, Excuse me. I find that the OP misses some info. I rewrite it again: I learn Python function call on tutorial. There is a link on this subject. http://robertheaton.com/2014/02/09/pythons-pass-by-object-reference-as-explained-by-philip-k

Re: Question about Pass-by-object-reference?

On Tuesday, July 22, 2014 3:32:19 PM UTC-4, Ned Batchelder wrote: On 7/22/14 3:04 PM, fl wrote: it is here: http://nedbatchelder.com/text/names.html When I enter the command lines on my computer: I recommend putting the code into a .py file, and running it all at once. Then if it doesn't

Why does not pprint work?

Hi, I read web tutorial at: http://nedbatchelder.com/blog/201308/names_and_values_making_a_game_board.html I enter the example lines of that website: import pprint board = [ [0]*8 ] * 8 pprint(board) It echos error with Python 2.7: Traceback (most recent call last): File

Re: Why does not pprint work?

On Tuesday, July 22, 2014 5:51:07 PM UTC-4, emile wrote: On 07/22/2014 02:42 PM, fl wrote: pprint is a module name -- you need to invoke the pprint function from within the pprint module: pprint.pprint(board) Thanks. I am curious about the two pprint. Is it the first pprint the name

Re: Question about Pass-by-object-reference?

On Tuesday, July 22, 2014 4:46:25 PM UTC-4, emile wrote: On 07/22/2014 01:35 PM, Peter Pearson wrote: def reassign(mylist): # no reason to shadow the list builtin mylist[:] = [0,1] mylist = [1] reassign(mylist) mylist Emile Thanks for your example. I do not find the explanation of

Re: Question about Pass-by-object-reference?

On Tuesday, July 22, 2014 4:46:25 PM UTC-4, emile wrote: On 07/22/2014 01:35 PM, Peter Pearson wrote: def reassign(mylist): # no reason to shadow the list builtin mylist[:] = [0,1] mylist = [1] reassign(mylist) mylist Emile I have a new question on the code. When I run it in a

Re: Question about Pass-by-object-reference?

On Tuesday, July 22, 2014 4:35:33 PM UTC-4, Peter Pearson wrote: On Tue, 22 Jul 2014 12:34:51 -0700 (PDT), fl r...@gmail.com wrote: When you say def reassign(list), that means I'm defining a function to which the caller will pass one object, and within this function I'm going to refer

Re: Question about Pass-by-object-reference?

On Tuesday, July 22, 2014 8:27:15 PM UTC-4, Terry Reedy wrote: When you call a function, Python binds function parameter names to argument objects in the function's local namespace, the same as in name assignments. Given def f(a, b): pass a call f(1, 'x') starts by executing a, b = 1, 'x'

Where is the function of Repr.repr1() in this example?

Hi, I run the example code below from website: https://docs.python.org/2/library/repr.html#repr.Repr.repr1 If I run these lines from an editor, it echoes: open file '...at 0x01EF4020 dsfdsf # entered letters If I only run the last line (hoping the same effect with running from the

How to install data analysis pandas toolkit?

Hi, I download data analysis pandas toolkit (Windows 32 version) to my PC: pandas-0.14.0.win32-py2.7.exe After I run it, I still cannot import the module: import pandas as pd No module named numpy Traceback (most recent call last): File interactive input, line 1, in module File

Re: How to install data analysis pandas toolkit?

On Wednesday, July 23, 2014 8:30:00 PM UTC-4, fl wrote: I have figured it out. It is installed under Cygwin. Although there are some errors in the process, it works now. Thanks, -- https://mail.python.org/mailman/listinfo/python-list

What is the simplest method to get a vector result?

Hi, I have read a lot about Python, but it still has a problem now on a simple exercise. For example, I want to generate a sine curve. First, I get a time sequence: index=range(100) I import math module, try to calculate sine with math.sin(index*math.pi/2) but it fails. It is possible to

How can I import unnecessary_math?

Hi, I want to write some test code. Some on-line tutorials have such codes: from unnecessary_math import multiply When it runs, it has errors: from unnecessary_math import multiply Traceback (most recent call last): File interactive input, line 1, in module ImportError: No module named

Re: How can I import unnecessary_math?

On Thursday, July 24, 2014 1:37:49 PM UTC-4, Chris Angelico wrote: On Fri, Jul 25, 2014 at 3:33 AM, fl r...@gmail.com wrote: Hi, I want to write some test code. Some on-line tutorials have such codes: from unnecessary_math import multiply Which tutorials? That's where you'll find

Re: How can I import unnecessary_math?

On Thursday, July 24, 2014 1:48:02 PM UTC-4, fl wrote: On Thursday, July 24, 2014 1:37:49 PM UTC-4, Chris Angelico wrote: On Fri, Jul 25, 2014 at 3:33 AM, fl rx...@gmail.com wrote: Thanks. The source of that snippet is from this link: http://pythontesting.net/framework/nose/nose

Re: How can I import unnecessary_math?

On Thursday, July 24, 2014 1:58:45 PM UTC-4, Chris Angelico wrote: On Fri, Jul 25, 2014 at 3:54 AM, fl rxj...@gmail.com wrote: @with_setup(my_setup_function, my_teardown_function) def test_numbers_3_4(): print 'test_numbers_3_4 actual test code

How to place several import .... lines in one .py file?

Hi, I have seen several kinds of module import examples, but most of the programs are small and less content. They only have one or two module import. I'll use the following modules in a small project. I would like to know whether it is appropriate to put all of them at the file header, like

Re: What is the simplest method to get a vector result?

On Thursday, July 24, 2014 10:25:52 AM UTC-4, Marko Rauhamaa wrote: #!/usr/bin/env python3 import math for x in range(0, 361, 15): print(int((math.sin(x / 180 * math.pi) + 1) * 30 + 0.5) * + *) Marko

How to index an array with even steps?

Hi, I have an array arr which is indexed from 0 to 999. I would like to construct a column in two steps. The first step is input from 200 data, evenly spread from 0 to 999 of the target array. Then, I want to use interpolate it from 200 to 1000 with interpolate method. In Python, ':' is used to

Re: How to index an array with even steps?

On Friday, July 25, 2014 7:45:31 AM UTC-4, fl wrote: to 999 of the target array. Then, I want to use interpolate it from 200 to 1000 with interpolate method. In Python, ':' is used to indicate range (while in Matlab I know it can be used to control steps). How to index an array with 0

Re: What is the simplest method to get a vector result?

On Thursday, July 24, 2014 9:49:14 AM UTC-4, Vlastimil Brom wrote: 2014-07-24 14:53 GMT+02:00 fl rxj@gmail.com: internally): http://mpmath.org/ Using the sensible defaults, the plotting of a function can be as simple as: mpmath.plot(mpmath.sin) As for your original question, you can

Re: What is the simplest method to get a vector result?

On Friday, July 25, 2014 8:37:14 PM UTC-4, Ian wrote: On Fri, Jul 25, 2014 at 5:08 PM, fl rx...@gmail.com wrote: Do you have other ways to import? (I find the above import a little more letters) What's wrong with: import numpy I was wrong, maybe some careless key inputs. import numpy

What meaning of this hello %s you are %s years old % x

Hi, I get a post on tuple, see below please, on line. It seems that something is missing. I want to learn tuple from this example as well. Could you explain it to me (a tuple % another tuple)? Thanks, http://stackoverflow.com/questions/1708510/python-list-vs-tuple-when-to-use-each In

Question about 'x' in pymc.invlogit(a+b*x)

Hi, I once learnt Python for a few weeks. Now, I try to using a Python package pymc. It has the following example code: import pymc import numpy as np n = 5*np.ones(4,dtype=int) x = np.array([-.86,-.3,-.05,.73]) alpha = pymc.Normal('alpha',mu=0,tau=.01) beta = pymc.Normal('beta',mu=0,tau=.01)

Re: Question about python package numpy

On Sunday, March 1, 2015 at 1:25:59 PM UTC-8, Andrea D'Amore wrote: On 2015-03-01 20:32:34 +, fl said: import numpy it succeeds. On http://wiki.scipy.org/Cookbook, it shows some interesting code example snippet, such as Cookbook / ParticleFilter, Markov chain etc. I don't know how

Question about python package numpy

Hi, It is difficult to install numpy package for my PC Windows 7, 64-bit OS. In the end, I install Enthought Canopy, which is recommended on line because it does install numpy automatically. Now, I can test it with import numpy it succeeds. On http://wiki.scipy.org/Cookbook, it shows some

Could you explain lambda function to me?

Hi, I see the description of lambda at the online tutorial, but I cannot understand it. '42' is transferred to the function. What 'x' value should be? I do not see it says that it is '0'. And, what is 'x'? def make_incrementor(n): ... return lambda x: x + n ... f =

Please help on this sorted function

Hi, I try to learn sorted(). With the tutorial example: ff=sorted({1: 'D', 2: 'B', 3: 'B', 4: 'E', 5: 'A'}) ff [1, 2, 3, 4, 5] I don't see what sorted does in this dictionary, i.e. the sequence of 1..5 is unchanged. Could you explain it to me? Thanks, --

Re: Please help on this sorted function

On Tuesday, June 2, 2015 at 1:20:40 PM UTC-7, fl wrote: Hi, I try to learn sorted(). With the tutorial example: ff=sorted({1: 'D', 2: 'B', 3: 'B', 4: 'E', 5: 'A'}) ff [1, 2, 3, 4, 5] I don't see what sorted does in this dictionary, i.e. the sequence of 1..5 is unchanged

What is the difference between list() and list?

Hi, I find the following results are interesting, but I don't know the difference between list() and list. nums=list() nums [] xx=list xx type 'list' nums [] print(xx) type 'list' print(nums) [] Could you tell me that? Thanks, --

Can Python function return multiple data?

Hi, I just see the tutorial says Python can return value in function, it does not say multiple data results return situation. In C, it is possible. How about Python on a multiple data return requirement? Thanks, -- https://mail.python.org/mailman/listinfo/python-list

Re: Can Python function return multiple data?

, fl rxj...@gmail.com wrote: Hi, I just see the tutorial says Python can return value in function, it does not say multiple data results return situation. In C, it is possible. How about Python on a multiple data return requirement? Thanks, -- https://mail.python.org

Could you give me the detail process of 'make_incrementor(22)(33)'?

Hi, I read a tutorial on lambda on line. I don't think that I am clear about the last line in its example code. It gives two parameters (22, 23). Is 22 for n, and 23 for x? Or, it creates two functions first. Then, each function gets 22 while the other function gets 23? Please help me on this

Could you explain why this program runs?

Hi, I download and install pyPDF2 library online. It says the test can run by: python -m unittest Tests.tests tests.py is under folder PyPDF2-master\Tests\ The above command line does run and give output message, but I don't understand why it run after I read tests.py:

Re: Could you explain why this program runs?

On Thursday, June 25, 2015 at 8:20:52 AM UTC-7, fl wrote: Hi, I download and install pyPDF2 library online. It says the test can run by: python -m unittest Tests.tests tests.py is under folder PyPDF2-master\Tests\ The above command line does run and give output message, but I

Could you explain [1, 2, 3].remove(2) to me?

Hi, I see a code snippet online: [1, 2, 3].remove(42) after I modify it to: [1, 2, 3].remove(2) and aa=[1, 2, 3].remove(2) I don't know where the result goes. Could you help me on the question? Thanks, -- https://mail.python.org/mailman/listinfo/python-list

Can anybody explain the '-' in a 2-D creation code?

Hi, I read Ned's tutorial on Python. It is very interesting. On its last example, I cannot understand the '_' in: board=[[0]*8 for _ in range(8)] I know '_' is the precious answer, but it is still unclear what it is in the above line. Can you explain it to me? Thanks, --

Re: Can anybody explain the '-' in a 2-D creation code?

On Thursday, June 25, 2015 at 6:24:07 PM UTC-7, Mark Lawrence wrote: On 26/06/2015 02:07, fl wrote: Hi, I read Ned's tutorial on Python. It is very interesting. On its last example, I cannot understand the '_' in: board=[[0]*8 for _ in range(8)] I know '_' is the precious

Could you explain this rebinding (or some other action) on nums = nums?

Hi, I read a blog written by Ned and find it is very interesting, but I am still unclear it in some parts. In the following example, I am almost lost at the last line: nums = num Could anyone explain it in a more detail to me? Thanks, ... The reason is that list

Re: Why does the unit test fail of the pyPDF2 package?

On Wednesday, June 24, 2015 at 9:54:12 AM UTC-7, fl wrote: Hi, I want to learn some coding on PDF. After I download and install pyPDF2, it cannot pass unit test, which is coming from the package. I put a screen shot link here to show the console message: http://tinypic.com/view.php?pic

Why does the unit test fail of the pyPDF2 package?

Hi, I want to learn some coding on PDF. After I download and install pyPDF2, it cannot pass unit test, which is coming from the package. I put a screen shot link here to show the console message: http://tinypic.com/view.php?pic=fbdpg0s=8#.VYre8_lVhBc [IMG]http://i57.tinypic.com/fbdpg0.png[/IMG]

Re: Why does the unit test fail of the pyPDF2 package?

On Wednesday, June 24, 2015 at 9:54:12 AM UTC-7, fl wrote: Hi, I want to learn some coding on PDF. After I download and install pyPDF2, it cannot pass unit test, which is coming from the package. I put a screen shot link here to show the console message: http://tinypic.com/view.php?pic

Re: Why does the unit test fail of the pyPDF2 package?

On Wednesday, June 24, 2015 at 9:54:12 AM UTC-7, fl wrote: Hi, I want to learn some coding on PDF. After I download and install pyPDF2, it cannot pass unit test, which is coming from the package. I put a screen shot link here to show the console message: http://tinypic.com/view.php?pic

What use for reversed()?

Hi, I have a string b='1234'. I run: br=reversed(b) I hope that I can print out '4321' by: for br in b but it complains: SyntaxError: invalid syntax My questions: 1. What use for reversed(). I do not find an example on web. 2. If reversed() is wrong the my purpose, what method can do it?

Are there any other better ways to access a single bit of string of digits?

Hi, I am new to Python. I would manipulate a string of hex numbers. If the first digit is bigger than 7, the first two digits are required to add 4. For example, '8022_3345' will be changed to '8422_3345'. The underscore between two 4-digit's was generated previously (i.e. it is already in the

Re: Are there any other better ways to access a single bit of string of digits?

On Sunday, May 31, 2015 at 12:53:19 PM UTC-7, Denis McMahon wrote: On Sun, 31 May 2015 11:36:35 -0700, fl wrote: I am new to Python. I would manipulate a string of hex numbers. If the first digit is bigger than 7, the first two digits are required to add 4. What happens if the first two

Re: What use for reversed()?

On Sunday, May 31, 2015 at 4:23:19 PM UTC-7, Tim Delaney wrote: On 1 June 2015 at 05:40, fl rxj...@gmail.com wrote: Hi, The for statement must have a colon at the end of line e.g. a complete for statement and block is: for br in b:     print br This will output the characters one per

Where is 'palindrome' defined?

Hi, When I search solution of reverse a string/number, I came across a short function online: def palindrome(num): return str(num) == str(num)[::-1] I thought that it is a general function. And with the following variable: a '1234_' parlindrome(a) Traceback (most recent call

Re: What use for reversed()?

On Sunday, May 31, 2015 at 12:59:47 PM UTC-7, Denis McMahon wrote: On Sun, 31 May 2015 12:40:19 -0700, fl wrote: reversed returns an iterator, not a list, so it returns the reversed list of elements one at a time. You can use list() or create a list from reversed and then join the result

A simple print cannot run in Python Shell

Hi, When I try the following (They are saved in a main.py file) #!/usr/bin/python print r'C:\\nowhere' It works as the tutorial, i.e. it echoes in a Windows 7 command console: C:\\nowhere When I run the following command in a Python 2.7.9 Shell on Windows 7, print r'C:\\nowhere'

How to access the low digits of a list

Hi, I have a list: lines ['12', '42', '49', '156', '225', '36', '49', '164', '11181', '3100'] I want to access the last two digits. That is: ['12', '42', '49', '56', '25', '36', '49', '64', '81', '00'] When I try to use lines[3][0] is '1' lines[3][1] is '5' lines[3][2] is '6' I

What use of string module?

Hi, I read the online help about string. It lists string constants, string formatting, template strings and string functions. After reading these, I am still puzzled about how to use the string module. Could you show me a few example about this module? Thanks --

Re: Where is 'palindrome' defined?

On Sunday, May 31, 2015 at 9:46:56 PM UTC-7, fl wrote: Hi, When I search solution of reverse a string/number, I came across a short function online: def palindrome(num): return str(num) == str(num)[::-1] I thought that it is a general function. And with the following variable

How to use an iterator?

Hi, I read the online tutorial on iterator: https://docs.python.org/2/library/itertools.html I have no idea on how to use this one: itertools.count(start=0, step=1) BTW, I am using Python 2.7.9 on Windows 7. I even input the following: def count(start=0, step=1): # count(10) -- 10 11

How to understand '_' in these tests?

Hi, I just know that '_' is the last result in the Python interpreter. I feel that it is like 'ans' in Matlab. When I run the following commands. The result of '_' are always '4'. Because I have tried several commands, such as reversed('fred'), xx and rx, '4' are always there. What is your

Is it useful for re.M in this example?

Hi, I follow a web site on learning Python re. I have read the function description of re.m, as below. re.MMakes $ match the end of a line (not just the end of the string) and makes ^ match the start of any line (not just the start of the string). But I don't see the reason to put re.M

What is wrong in this example code?

Hi, I run a code snippet from link: http://www.python-course.eu/inheritance_example.php It is found that there is an error in this loop: for i in xrange(1): x.tick() print(x) SyntaxError: invalid syntax I have modified it to: for i in x range(1): x.tick() print(x) SyntaxError:

Re: What is wrong in this example code?

On Thursday, November 12, 2015 at 8:58:33 AM UTC-5, fl wrote: > Hi, > > I run a code snippet from link: > http://www.python-course.eu/inheritance_example.php > > It is found that there is an error in this loop: > > for i in xrange(1): > x.tick() > print(x)

What is '@' for

Hi, I read the following code snippet. A question is here about '@'. I don't find the answer online yet. What function is it here? BTW, below is for printing out? """theta = logit^{-1}(a+b)""" but I don't see it is printed when the following could have been called. Are you sure it would

Where is decorator in this example code?

Hi, I am learning decorator following this link: http://thecodeship.com/patterns/guide-to-python-function-decorators/ When I read decorator on class, I don't see decorator taking in effect. In the following code snippet, there is the same print out if I comment out two lines 'def

Re: Where is decorator in this example code?

On Saturday, November 14, 2015 at 7:11:11 AM UTC-5, fl wrote: > Hi, > > I am learning decorator following this link: > > http://thecodeship.com/patterns/guide-to-python-function-decorators/ > > When I read decorator on class, I don't see decorator taking in effect. &g

What function is 'u0, j = random(), 0'?

Hi, When I read the below code, I cannot make the last line (with ##) out. def res(weights): n = len(weights) indices = [] C = [0.] + [sum(weights[:i+1]) for i in range(n)] u0, j = random(), 0 ## If I run below code on console, it will say an error. uu, 0.1, 0 What

Re: What meaning is of '#!python'?

On Saturday, November 14, 2015 at 8:58:57 PM UTC-5, Chris Angelico wrote: > On Sun, Nov 15, 2015 at 12:54 PM, fl wrote: > > I see an example Python code has such a line at the file beginning: > > > > #!python > > > > > > Is there some meaning about it? &g

Question about yield

Hi, I have read a couple of tutorial on yield. The following code snippet still gives me a shock. I am told yield is a little like return. I only see one yield in the tutorial examples. Here it has two yields. And there are three variables following keyword yield. I have not tried debug function

Re: Where is decorator in this example code?

On Saturday, November 14, 2015 at 7:38:09 AM UTC-5, Chris Warrick wrote: > On 14 November 2015 at 13:13, fl <rx**g...@gmail.com> wrote: > > On Saturday, November 14, 2015 at 7:11:11 AM UTC-5, fl wrote: > >> Hi, > >> > >> I am learning decorator following t

What meaning is 'a[0:10:2]'?

hi, When I learn slice, I have a new question on the help file. If I set: pp=a[0:10:2] pp is array([1, 3]) I don't know how a[0:10:2] gives array([1, 3]). I know matlab a lot, but here it seems quite different. Could you tell me what meaning a[0:10:2] is? Thanks, class slice(object) |

Why does 'as' not recognized?

Hi, When I try the following, python does not know 'as'. Why doesn't it? Thanks, >>> cats = ['Tom', 'Snappy', 'Kitty', 'Jessie', 'Chester'] >>> >>> type(cats) >>> cats[2] 'Kitty' >>> as=cats[2] SyntaxError: invalid syntax >>> as=cats SyntaxError: invalid syntax >>> as SyntaxError: invalid

How to get 'od' run?

Hi, I am learning python. I see a previous post has such code: >>> data = '"binääridataa"\n'.encode('utf-8') >>> f = open('roska.txt', 'wb') >>> f.write(data) 17 >>> f.close() The .encode methods produced a bytestring, which Python likes to display as ASCII characters

Help on savefig parameters

Hi, I find the parameters of savefig function has the similar format of that of main(*argc, **argv) in C. I have tried with savefig("temp.pdf", format='pdf'), and it works. I get the help content of savefig() as below. But I cannot understand why they also give: savefig(fname, dpi=None,

Is there any reason to introduce this intermediate variable (sz)?

Hi, I find the following code snippet, which is useful in my project: n_iter = 50 sz = (n_iter,) # size of array x = -0.37727 z = np.random.normal(x,0.1,size=sz) Q = 1e-5 # process variance # allocate space for arrays xhat=np.zeros(sz) P=np.zeros(sz) I learn Python now and

What is wrong this wrapper (decorator)?

Hi, I follow a tutorial to learn decorator: http://simeonfranklin.com/blog/2012/jul/1/python-decorators-in-12-steps/ I use Enthought Canopy to run the following code. It is really strange that the wrapper does not take effect. In fact, I go back to the basic way (not with @): wrapper(sub(two,

Re: What is wrong this wrapper (decorator)?

On Saturday, November 14, 2015 at 12:23:50 PM UTC-5, fl wrote: > Hi, > > I follow a tutorial to learn decorator: > > http://simeonfranklin.com/blog/2012/jul/1/python-decorators-in-12-steps/ > > I use Enthought Canopy to run the following code. > It is really stran

What is the right way to import a package?

Hi, I want to use a code snippet found on-line. It has such content: from numpy import * dt = 0.1 # Initialization of state matrices X = array([[0.0], [0.0], [0.1], [0.1]]) # Measurement matrices Y = array([[X[0,0] + abs(randn(1)[0])], [X[1,0] + abs(randn(1)[0])]]) When the above content is

Can Canopy Express (Free) allow install a new package (PyBayes) to it?

I am using Canopy Express (Free) version. I want to install PyBayes package, but I don't see it in Package Manager of Canopy. Can I install PyBayes to Canopy? Now, Canopy is the default Python on my Windows 7 PC. If Canopy does not allow to install PyBayes into it, can I install PyBayes to the

What meaning is of '#!python'?

Hi, I see an example Python code has such a line at the file beginning: #!python Is there some meaning about it? Thanks, -- https://mail.python.org/mailman/listinfo/python-list

What use is this class?

Hi, When I search around tutorial about None, I came across this link: http://jaredgrubb.blogspot.ca/2009/04/python-is-none-vs-none.html I don't understand what use of this class example: >>> class Zero(): # a class that is zero ...def __nonzero__(self): ... return False I can

variable vs. object

Hi, I read several parts on line about Python that everything in Python is an object. Yes, it is a key difference with other languages. Then, I read a page it says variables: global and local variable at: http://www.tutorialspoint.com/python/python_functions.htm I have a question that whether

Question about code writing '% i, callback'

Hi, I come across the following code snippet. for i in range(10): def callback(): print "clicked button", i UI.Button("button %s" % i, callback) The content inside parenthesis in last line is strange to me. "button %s" % i, callback That is, the writing looks like

Re: Question about code writing '% i, callback'

On Monday, November 30, 2015 at 12:02:57 PM UTC-5, Ian wrote: > On Mon, Nov 30, 2015 at 10:44 AM, fl wrote: > > I come across the following code snippet. > > > > for i in range(10): > > def callback(): > > print "clicked button", i

Re: Question about code writing '% i, callback'

On Monday, November 30, 2015 at 12:37:52 PM UTC-5, Terry Reedy wrote: > On 11/30/2015 11:44 AM, fl wrote: > > > I come across the following code snippet. > > > for i in range(10): > > def callback(): > > print "clicked button", i &

Re: Question about code writing '% i, callback'

On Monday, November 30, 2015 at 11:44:44 AM UTC-5, fl wrote: > Hi, > > I come across the following code snippet. > > > > > > for i in range(10): > def callback(): > print "clicked button", i > UI.Button("button %s" % i

Re: Could you explain this rebinding (or some other action) on "nums = nums"?

On Wednesday, June 24, 2015 at 8:17:08 PM UTC-4, Chris Angelico wrote: > On Thu, Jun 25, 2015 at 9:52 AM, fl wrote: > > The reason is that list implements __iadd__ like this (except in C, not > > Python): > > > > class List: > > def __iadd__(self, othe

Question about output different with command dis.dis(code)

Hi, I see the following from a previous post: Python 1.5.2 (#1, Aug 27 2012, 09:09:18) [GCC 4.1.2 20080704 (Red Hat 4.1.2-52)] on linux2 Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam >>> import dis >>> code = compile("(1, 2, 3)", "", "eval") >>> dis.dis(code) 0

Re: Is there any reason to introduce this intermediate variable (sz)?

On Tuesday, November 17, 2015 at 4:03:05 PM UTC-5, John Gordon wrote: > In <bad9ac66-38aa-4445-a486-6df0e9c77...@googlegroups.com> fl <@gmail.com> > writes: > > > correctly. Could you see something useful with variable 'sz'? > > 'sz' is fewer characters than

Re: What is a function parameter =[] for?

On Wednesday, November 18, 2015 at 5:38:45 PM UTC-5, fl wrote: > On Wednesday, November 18, 2015 at 5:12:44 PM UTC-5, Ian wrote: > > On Wed, Nov 18, 2015 at 2:08 PM, fl wrote: > > > Hi, > > > > > > I have tried the below function and find that it can remem

Re: What is a function parameter =[] for?

On Wednesday, November 18, 2015 at 7:15:05 PM UTC-5, Chris Angelico wrote: > On Thu, Nov 19, 2015 at 11:02 AM, Ian Kelly wrote: > > On Wed, Nov 18, 2015 at 4:22 PM, Chris Angelico wrote: > >> On Thu, Nov 19, 2015 at 10:14 AM, BartC

Question about 'print' in a loop

Hi, >From previous post, I get many helpful replies. Now I have a new question when I run this example code: - sq=[] for xx in range(5): print 'here' sq.append(lambda:xx**2) here here here here here xx Out[150]: 4 sq[2]() Out[151]: 16 sq[3]() Out[152]: 16 / There

Re: What is a function parameter =[] for?

On Wednesday, November 18, 2015 at 5:12:44 PM UTC-5, Ian wrote: > On Wed, Nov 18, 2015 at 2:08 PM, fl wrote: > > Hi, > > > > I have tried the below function and find that it can remember the previous > > setting value to 'val'. I think the second parameter has somethin

Could you explain why the following generates 4 same elements list?

Hi, I cannot reason out why the code: def mpl(): return [lambda x : i * x for i in range(4)] print [m(2) for m in mpl()] / has result: [6, 6, 6, 6] I have tried to simplify the above code to an easy understanding form, but fails. Either the modified code does not

Re: Question about 'print' in a loop

On Wednesday, November 18, 2015 at 10:11:24 PM UTC-5, Chris Angelico wrote: > On Thu, Nov 19, 2015 at 1:55 PM, fl wrote: > > There are only one time 5 'here' printed out, but there is no 'here' print > > out in thereafter call sq[2]() etc. How to understand this phenomenon? >

Is there an meaning of '[[]]' in a list?

Hi, In the previous exercises, I see list: cc=[[],[],[]] Then, I can have this: ccc=[[[]],[[]],[[]]] I can also have ccc[0] Out[158]: [[]] ccc[0]='o' ccc Out[163]: ['o', [[]], [[]]] I have question: Is there any difference between [[]] and []? [[]] can have deeper assignment and use than

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