Re: Newbie: use of built-in exceptions
Chris “Kwpolska” Warrick wrote: There are no rules. You should use common sense instead: if the exception fits your needs (eg. ValueError when incorrect output occurs) then use it. Ok, thanks for the tip. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Newbie: use of built-in exceptions
Are there any guidelines on the use (and abuse) of Python's built-in exceptions, telling where it's ok to raise them and where it's preferable to define custom exceptions instead? Thanks in advance, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: static typing?
Ben Finney wrote: Rui Maciel rui.mac...@gmail.com writes: Is there any pythonic way to perform static typing? I think no; static typing is inherently un-Pythonic. Python provides strong, dynamic typing. Enjoy it! Bummer. Does anyone care to enlighten a newbie? Is there some specific problem you think needs static typing? Perhaps you could start a new thread, giving an example where you are having trouble and you think static typing would help. It would be nice if some functions threw an error if they were passed a type they don't support or weren't designed to handle. That would avoid having to deal with some bugs which otherwise would never happen. To avoid this sort of error, I've been testing arguments passed to some functions based on their type, and raising TypeError when necessariy, but surely there must be a better, more pythonic way to handle this issue. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: static typing?
Steven D'Aprano wrote: On Mon, 05 Aug 2013 21:46:57 +0100, Rui Maciel wrote: Is there any pythonic way to perform static typing? After searching the web I've stumbled on a significant number of comments that appear to cover static typing as a proof of concept , but in the process I've found no tutorial on how to implement it. Try Cobra instead. It's Python-like syntax, but allows static typing. http://cobra-language.com/ Thanks for the suggestion, but switching Python for another programming language would defeat the purpose of learning Python. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: static typing?
Gary Herron wrote: The Pythonic way is to *enjoy* the freedom and flexibility and power of dynamic typing. If you are stepping out of a static typing language into Python, don't step just half way. Embrace dynamic typing. (Like any freedom, it can bite you at times, but that's no reason to hobble Python with static typing.) What's the Python way of dealing with objects being passed to a function that aren't of a certain type, have specific attributes of a specific type, nor support a specific interface? Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: static typing?
Joshua Landau wrote: Unless you have a very good reason, don't do this. It's a damn pain when functions won't accept my custom types with equivalent functionality -- Python's a duck-typed language and it should behave like one. In that case what's the pythonic way to deal with standard cases like this one? code class SomeModel(object): def __init__(self): self.label = this is a label attribute def accept(self, visitor): visitor.visit(self) print(visited: , self.label) class AbstractVisitor(object): def visit(self, element): pass class ConcreteVisitorA(AbstractVisitor): def visit(self, element): element.label = ConcreteVisitorA operated on this model class ConcreteVisitorB(AbstractVisitor): def visit(self, element): element.label = ConcreteVisitorB operated on this model model = SomeModel() operatorA = ConcreteVisitorA() model.accept(operatorA) operatorB = ConcreteVisitorB() model.accept(operatorA) not_a_valid_type = foo model.accept(not_a_valid_type) /python Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: static typing?
Joshua Landau wrote: What's the actual problem you're facing? Where do you feel that you need to verify types? A standard case would be when there's a function which is designed expecting that all operands support a specific interface or contain specific attributes. In other words, when passing an unsupported type causes problems. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: static typing?
Chris Angelico wrote: On Tue, Aug 6, 2013 at 10:01 AM, Rui Maciel rui.mac...@gmail.com wrote: It would be nice if some functions threw an error if they were passed a type they don't support or weren't designed to handle. That would avoid having to deal with some bugs which otherwise would never happen. To avoid this sort of error, I've been testing arguments passed to some functions based on their type, and raising TypeError when necessariy, but surely there must be a better, more pythonic way to handle this issue. def add_three_values(x,y,z): return x+y+z Do you want to test these values for compatibility? Remember, you could take a mixture of types, as most of the numeric types can safely be added. You can also add strings, or lists, but you can't mix them. And look! It already raises TypeError if it's given something unsuitable: If the type problems aren't caught right away when the invalid types are passed to a function then the problem may only manifest itself in some far away point in the code, making this bug needlessly harder to spot and fix, and making the whole ordeal needlessly too time consuming. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Newbie: static typing?
Is there any pythonic way to perform static typing? After searching the web I've stumbled on a significant number of comments that appear to cover static typing as a proof of concept , but in the process I've found no tutorial on how to implement it. Does anyone care to enlighten a newbie? Thanks in advance, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Newbie: Python 3 and web applications?
I'm currently learning Python, and I've been focusing on Python3. To try to kill two birds with one stone, I would also like to learn the basics of writing small web applications. These web applications don't need to do much more than provide an interface to a small database, and they may not even be required to be accessible outside of a LAN. Does anyone have any tips on what's the best way to start off this adventure? Thanks in advance, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Rick Johnson wrote: On Monday, June 10, 2013 8:18:52 AM UTC-5, Rui Maciel wrote: [...] code class Point: position = [] def __init__(self, x, y, z = 0): self.position = [x, y, z] Firstly. Why would you define a Point object that holds it's x,y,z values in a list attribute? Why not store them as self.x, self.y and self.z? snip/ The position in space is represented as a vector, which is then used in a series of operations. Currently I'm using numpy arrays to represent vectors. Secondly, why would store the position of the Point as a class attribute? snip/ I've answered this 3 days ago. I'm still learning Python, and python.org's tutorial on classes didn't explicitly covered the differences between class and instance attributes. If you construct your code properly this can be achieved. If each point is an object, and lines are merely holding references to two point objects that define the start and end position of an imaginary line, then updates on the points will be reflected in the Line object. This was already covered three days ago in another post in this thread. I'll quote the post below quote I've tested the following: code model = Model() model.points.append(Point(1,2)) model.points.append(Point(1,4)) line = Line( model.points[0], model.points[1]) # Case A: this works model.points[0].position = [2,3,4] line.points # Case B: this doesn't work test.model.points[0] = test.Point(5,4,7) line.points /code Is there a Python way of getting the same effect with Case B? /quote Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Version Control Software
Roy Smith wrote: In article 98c13a55-dbf2-46a7-a2aa-8c5f052ff...@googlegroups.com, cutems93 ms2...@cornell.edu wrote: I am looking for an appropriate version control software for python development, and need professionals' help to make a good decision. Currently I am considering four software: git, SVN, CVS, and Mercurial. CVS is hopelessly obsolete. SVN pretty much the same. I would say that SVN does have its uses, but managing software repositories isn't one of them due to the wealth of available alternatives out there which are far better than it. Git and Mercurial are essentially identical in terms of features; which you like is as much a matter of personal preference as anything else. Pick one and learn it. I agree, but there is a feature Git provides right out of the box which is extremelly useful but Mercurial supports only as a non-standard module: the git stash feature. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Newbie: standard way to add version, author and license to a source file?
Is there any PEP that establishes a standard way to specify the version number of a source code file, as well as its authors and what license it's distributed under? Thanks in advance, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Chris Angelico wrote: Just FYI, Rick Johnson (aka Ranting Rick) is a known troll. Don't let him goad you :) Follow other people's advice, and take Rick's posts with a grain of salt. Sometimes he has a good point to make (more often when he's talking about tkinter, which is his area of expertise), but frequently he spouts rubbish. I had no idea. Thanks for the headsup. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Newbie: question regarding references and class relationships
Let: - class Point be a data type which is used to define points in space - class Line be a data type which possesses an aggregate relationship with objects of type Point - class Model be a container class which stores collections of Point and Line objects Essentially, a Model object stores lists of Point objects and Line objects, and Line objects include references to Point objects which represent the starting and ending point of a line. To reflect this class relationship, I've defined the following classes: code class Point: position = [] def __init__(self, x, y, z = 0): self.position = [x, y, z] class Line: points = () def __init__(self, p_i, p_f): self.points = (p_i, p_f) class Model: points = [] lines = [] /code It would be nice if, whenever a Point object was updated, the Line objects which are associated with it could reflect those updates directly in Line.p_i and Line.p_f. What's the Python way of achieving the same effect? Thanks in advance, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Roy Smith wrote: Have you tried running the code you wrote? It does that already! When you do something like: my_list = [obj1, obj2] in Python, the objects are stored by reference (not just lists, all assignments are by reference). I've tested the following: code model = Model() model.points.append(Point(1,2)) model.points.append(Point(1,4)) line = Line( model.points[0], model.points[1]) # Case A: this works model.points[0].position = [2,3,4] line.points # Case B: this doesn't work test.model.points[0] = test.Point(5,4,7) line.points /code Is there a Python way of getting the same effect with Case B? Thanks in advance, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Peter Otten wrote: Don't add position = [] to your code. That's not a declaration, but a class attribute and in the long run it will cause nothing but trouble. Why's that? Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Rui Maciel wrote: # Case B: this doesn't work test.model.points[0] = test.Point(5,4,7) Disregard the test. bit. I was testing the code by importing the definitions as a module. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Peter Otten wrote: Rui Maciel wrote: Peter Otten wrote: Don't add position = [] to your code. That's not a declaration, but a class attribute and in the long run it will cause nothing but trouble. Why's that? Especially with mutable attributes it's hard to keep track whether you are operating on the instance or the class: class Point: ... position = [] ... def __init__(self, x, y, z): ... self.position = [x, y, z] ... a = Point(1, 2, 3) b = Point(10, 20, 30) a.position [1, 2, 3] del a.position a.position [] # did you expect that? del b.position b.position.extend([did you expect that?]) a.position ['did you expect that?'] del a.position Traceback (most recent call last): File stdin, line 1, in module AttributeError: position How do you guarantee that any object of a class has a specific set of attributes? Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Peter Otten wrote: Rui Maciel wrote: How do you guarantee that any object of a class has a specific set of attributes? You don't. What's your point regarding attribute assignments in class declarations, then? Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Peter Otten wrote: I don't understand the question. My original point was that you should omit class attributes that don't fulfill a technical purpose. You've said the following: quote class Point: Don't add position = [] to your code. That's not a declaration, but a class attribute and in the long run it will cause nothing but trouble. /quote We've established that you don't like attribute declarations, at least those you describe as not fulfill a technical purpose. What I don't understand is why you claim that that would cause nothing but trouble. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Peter Otten wrote: Have you read the code in the interpreter session I posted? If you do not agree that the demonstrated behaviour is puzzling I'll have to drop my claim... I don't see how it should be puzzling. You've deleted the attribute, so it ceassed to exist. Likewise if you can show a benefit of the position = [] line. I wrote the code that way to declare intent and help document the code. In this case that the class Point is expected to have an attribute named position which will point to a list. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Terry Jan Reedy wrote: On 6/10/2013 9:18 AM, Rui Maciel wrote: class Model: points = [] lines = [] Unless you actually need keep the points and lines ordered by entry order, or expect to keep sorting them by whatever, sets may be better than lists. Testing that a point or line is in the model will be faster, as will deleting one by its identify. Thanks for the tip, Terry. Sounds great. I'll update my code. Once again, thanks for the help, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Terry Jan Reedy wrote: Three answers: Look how much trouble it has already caused ;-) Since you are a self-declared newbie, believe us! Since, be definition, useless code can do no good, it can only cause trouble. Think about it. I don't doubt that there might good reasons for that, but it is always preferable to get the rationale behind a decision to be able to understand how things work and how to do things properly. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: question regarding references and class relationships
Dave Angel wrote: So why do you also have an instance attribute of the same name? Thanks to this thread, and after a bit of reading, I've finally managed to discover that in Python there are class attributes and instance attributes, the former working similarly to C++'s static member variables and the latter being more like proper member variables. And there was light. Python.org's tutorial could cover this issue a bit better than it does. Thanks for the help, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Ubuntu package python3 does not include tkinter
Steven D'Aprano wrote: Nobody forces you to do anything. Python is open source, and the source code is freely available. That goes both ways, with the added benefit that python-tkinter is already available in distro's official repositories. If you want to install it, go for it. Nothing stops you. If you don't then you aren't forced to install half the packages in the repository just to have a python interpreter in your system. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Ubuntu package python3 does not include tkinter
Chris Angelico wrote: 30 years ago, people weren't using Tk. And after 30 years gone by, some people still don't use Tk, let alone Tkinter. There is absolutely no reason to force them to install that if they don't need to. We've moved on beyond worrying about the odd kilobyte of space. That must be reason why you are the only one complaining about that. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Ubuntu package python3 does not include tkinter
Steven D'Aprano wrote: No, the job of the package system is to manage dependencies. It makes no guarantee about whether or not something will work. The purpose of establishing dependencies is to guarantee that once a software package is installed, all the necessary components needed for it to run properly are already present in the system or can be installed automatically. http://en.wikipedia.org/wiki/Dependency_hell Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Ubuntu package python3 does not include tkinter
lcrocker wrote: I understand that for something like a server distribution, but Ubuntu is a user-focused desktop distribution. It has a GUI, always. Irrelevant. The purpose of a distro like that is to give users a good experience. If I install Python on Windows, I get to use Python. On Ubuntu, I don't, and I think that will confuse some users. Nonsense. No one is keeping anyone off tkinter. If you want it, install it. There are official packages in the repositories such as python-tk and python3-tk. If someone else doesn't want them then they aren't forced to pack their Ubuntu systems with more cruft. There's nothing worse than being forced to install piles of irrelevant and useless stuff as a dependency to a fundamental package. I recently recommended Python to a friend who wants to start learning programming. Hurdles like this don't help someone like him. If your friend believes that having to do an extra pair of clicks or typing sudo apt-get install python-tk is an unbeatable hurdle then your friend's computer skills are awfully lacking and he won't have much success learning how to write programs. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Ubuntu package python3 does not include tkinter
Steven D'Aprano wrote: It's only easy to install a package on Ubuntu if you know that you have to, and can somehow work out the name of the package. No one actually has to install tkinter. That's the whole point of providing it as a separate package: only those who want to use it have to install it. The rest of us don't. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Ubuntu package python3 does not include tkinter
lcrocker wrote: I'm a programmer, I installed Tkinter, and use it. I'd like to deploy programs written with it to others. **Those** people know nothing about it, and **shouldn't have to**. They don't need to. The only person that needs to know what he is doing is you. You want to distribute a software package? Package it. Learn the very basics and set python-tkinter as a dependency. http://wiki.debian.org/Packaging Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Ubuntu package python3 does not include tkinter
Steven D'Aprano wrote: I think that if you are worrying about the overhead of the tkinter bindings for Python, you're guilty of premature optimization. I'm not worried about that. No one should be forced to install crap that they don't use or will ever need, no matter how great the average HD capacity is nowadays. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Functional vs. Object oriented API
Max Bucknell wrote: Hi, I'm currently learning Python, and it's going great. I've dabbled before, but really getting into it is good fun. To test myself, and not detract too much from my actual studies (mathematics), I've been writing my own package to do linear algebra, and I am unsure about how best to structure my API. For example, I have a vector class, that works like so: a = Vector([2, 7, 4]) b = Vector.j # unit vector in 3D y direction I also have a function to generate the dot product of these two vectors. In Java, such a function would be put as a method on the class and I would do something like: a.dot_product(b) 7 Not necessarily. That would only happen if that code was designed that way. It's quite possible, and desirable, that the dot product isn't implemented as a member function of the vector data type, and instead is implemented as an operator to be applied to two object. and that would be the end of it. But in Python, I can also have: dot_product(a, b) 7 Which of these two are preferred in Python? And are there any general guidelines for choosing between the two styles, or is it largely a matter of personal preference? The separation of concerns principle is a good guideline. This doesn't apply exclusively to Python; it essentiallyl applies to all programming languages. http://en.wikipedia.org/wiki/Separation_of_concerns There are significant advantages in separating the definition of a data type from the definition of the operations that are to be applied to it. If operations are decoupled from the data type then it's possible to preserve the definition of that data type eternally, while the operators that are written to operate on it can be added, tweaked and removed independently and at anyone's whims. Hope this helps, Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: In defence of 80-char lines
Steven D'Aprano wrote: Although PEP 8 is only compulsory for the Python standard library, many users like to stick to PEP 8 for external projects. http://www.python.org/dev/peps/pep-0008/ With perhaps one glaring exception: many people hate, or ignore, PEP 8's recommendation to limit lines to 80 characters. (Strictly speaking, 79 characters.) Here is a good defence of 80 char lines: http://wrongsideofmemphis.com/2013/03/25/80-chars-per-line-is-great/ The now arbitrary 80-column limit is a remnant of the limitations built into ancient terminals. Why not let the text editor auto-wrap the lines? They can do that now. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Why is Ruby on Rails more popular than Django?
rusi wrote: Anyone who's used emacs will know this as the bane of FLOSS software -- 100 ways of doing something and none perfect -- IOW too much spurious choice. This is a fallacy. Just because someone claims that there are 100 ways of doing something and none perfect, it doesn't mean that restricting choice leads to perfection. It doesn't. It only leads to getting stuck with a poor solution with no possibility of improving your life by switching to a better alternative. Worse, a complete lack of alternatives leads to a complete lack of competition, and therefore the absense of incentives to work on improvements. You know, progress. Choice is good. Don't pretend it isn't. It's one of the reasons we have stuff like Python or Ruby nowadays, for example. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Newbie
piterrr.dolin...@gmail.com wrote: snip/ So far I am getting the impression that Python is a toy language of some kind (similar to Basic of the early 80's), not really suitable for serious work. The only difference between these languages (admittedly, a serious one) is the existence of extensive libraries. Otherwise there would be no good reason for Python to exist. Nevertheless, it does exist and I have to learn it. As long as someone is paying for my time, that's OK with me. That's some military-grade trolling. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Newbie
Mitya Sirenef wrote: Looks very unclear and confusing to me. Whether it's C# or ruby or anything else, most devs don't indent like that; The Go programming language makes that style mandatory. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Newbie
Chris Angelico wrote: On Fri, Feb 22, 2013 at 10:58 PM, Rui Maciel rui.mac...@gmail.com wrote: Mitya Sirenef wrote: Looks very unclear and confusing to me. Whether it's C# or ruby or anything else, most devs don't indent like that; The Go programming language makes that style mandatory. [citation needed] What do you mean by that style? The OP's style with the 'if' indented? I just checked out golang.org for examples, and they're written in OTBS. Read Mitya Sirenef's post, specifically the bit I've replied to. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Is Python venerable?
rusi wrote: Heh! I am reminded: Some years ago a new reprint of Knuth's Art of Programming had on the back cover something to the effect that this was 'classical CS.' So what then is pop-CS, folk-CS? Knuth's work is undoubtedly classic. Classic: 1. of the first or highest quality, class, or rank: a classic piece of work. 2. serving as a standard, model, or guide: the classic method of teaching arithmetic. http://dictionary.reference.com/browse/classic Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Guy Steele on Parallel Programing
Xah Lee wrote: might be interesting. 〈Guy Steele on Parallel Programing〉 http://xahlee.org/comp/Guy_Steele_parallel_computing.html Very interesting. Thanks for the link. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Use the Source Luke
Raymond Hettinger wrote: Have any of you all seen other examples besides the Go language docs and the Python docs? Wasn't doxygen developed with that in mind? Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: [OT] Python like lanugages [was Re: After C++, what with Python?]
Tim Harig wrote: You still don't see many companies doing large scale internal development using Python and you definately don't see any doing external developement using a language that gives the customers full access to the source code. What you refered as full access to the source code only goes as far as the license which was imposed by the copyright holders lets it to go. If you distribute the source code along with the binaries but you only license your code if the licencees accept that they may look at the source code but they can't touch it then distributing the source code is essentially meaningless. There is a good reason why open source software is not the same thing as free software. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Strong typing vs. strong testing
namekuseijin wrote: in C I can have a function maximum(int a, int b) that will always work. Never blow up, and never give an invalid answer. If someone tries to call it incorrectly it is a compile error. In a dynamic typed language maximum(a, b) can be called with incorrect datatypes. Even if I make it so it can handle many types as you did above, it could still be inadvertantly called with a file handle for a parameter or some other type not provided for. So does Eckel and others, when they are writing their dynamically typed code advocate just letting the function blow up or give a bogus answer, or do they check for valid types passed? If they are checking for valid types it would seem that any benefits gained by not specifying type are lost by checking for type. And if they don't check for type it would seem that their code's error handling is poor. that is a lie. Compilation only makes sure that values provided at compilation-time are of the right datatype. What happens though is that in the real world, pretty much all computation depends on user provided values at runtime. See where are we heading? You are confusing two completely different and independent concepts, which is a language's typing sytem and input validation. TheFlyingDutchman pointed out the typical problems associated with weakly typed languages while you tried to contradict him by complaining about input sanity issues. The thing is, input sanity issues are perfectly independent of a language's typing system. Therefore, arguing about the need to perform sanity checks on programs written on language X or Y does nothing to tackle the issues related to passing a variable/object of the wrong type as a parameter to some function. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Strong typing vs. strong testing
George Neuner wrote: That's true. But it is a situation where the conversion to SI units loses precision and therefore probably shouldn't be done. snip/ I don't care to check it ... the fact that the SI unit involves 12 decimal places whereas the imperial unit involves 3 tells me the conversion probably shouldn't be done in a program that wants accuracy. Your comment is absurd for multiple reasons. As we are focusing on the computational aspect of this issue then I will only say this: If we are dealing with a computer representation of numbers then, as long as the numeric data type provides enough precision, it is perfectly irrelevant if a decimal representation of a certain number involves 12 or 3 decimal places. The only precision issues which affect a calculation is the ones arising from a) the ability to exactly represent a certain number in a specific representation and b) the precision errors produced by arithmetic operations. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Strong typing vs. strong testing
Pascal J. Bourguignon wrote: Nothing extraordinary here. Common Lisp is more efficient than C. http://www.lrde.epita.fr/~didier/research/verna.06.ecoop.pdf http://portal.acm.org/citation.cfm?id=1144168 I don't know if you are intentionally trying to be deceitful or if you honestly didn't spent much time thinking about this issue. To be brief I will only point out the following topics: a) no language is inherently more or less efficient than any other language. The efficiency aspect is only related to how those languages are implemented (i.e., the investments made in optimizing the compilers/interpreters) b) Just because someone invested enough effort to optimize a specific implementation of language X to run, under a specific scenario, a benchmark faster than some other implementation of language Y it doesn't mean that language X's implementation outperforms or even matches every implementation of language Y under every conceivable scenario. Regarding the links that you've provided, again I don't know if you intended to be dishonest or if you simply didn't read them. The first link, entitled Beating C in Scientific Computing Applications On the Behavior and Performance of LISP, Part 1, basically compares a highly optimized implementation of lisp (quite literally the current state of the art in COMMON -LISP compiler technology) with a standard, run of the mill C implementation by performing a very specific benchmark. If that wasn't enough, the C implementation they adopted to represent C was none other than GCC 4.0.3. As we all know, the 4.0 branch of GCC was still experimental an ran notoriously worse than the 3.4 branch[1]. But even though you've ignored this, the article's authors haven't. They've stated the following on their article: quote We must admit however that this point of view is not totally unjustified. Recent studies (Neuss, 2003; Quam, 2005) on various numerical computation algorithms find that LISP code compiled with C MU - CL can run at 60% of the speed of equivalent C code. /quote So, where exactly do you base your claims? Actually, it's hard to find a language that has no compiler generating faster code than C... Once again, I don't know if you are intentionally trying to be deceitful. If an undergraduate student happens to write a C compiler for a compiler class which employs no optimization whatsoevere then that will not mean that every single C compiler is incapable of generating efficient code. Rui Maciel [1] http://coyotegulch.com/reviews/gcc4/index.html -- http://mail.python.org/mailman/listinfo/python-list
Re: Fascinating interview by Richard Stallman at KTH on emacs history and internals
Kenneth Tilton wrote: What we do not have is any interesting amount of free as in speech software, because no one uses the GPL. You appear to be either confused or out of touch with reality. If that wasn't enough, your comment becomes a bit more amusing once we check your post's user agent. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Fascinating interview by Richard Stallman on Russia TV
Emmy Noether wrote: snip nonsense/ Mackenzie, bring a properly written documentation by FSF for example on emacs of gcc. I want to see where RMS got his ideas ? Did he invent all of them himself ? Is he giving proper references to the sources of the ideas ? Is that plagiarism ? I am sick of such jews/zionists like RMS, Roman Polansky, Bernard Madoff, Larry Ellison (he had to pay 100K in court to a chinese girl he screwed), Stephen Wolfram, Albert Einstein spreading anti-semitism by their flagrant unethical behaviour. snip more nonsense/ You are a lousy troll. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: A Exhibition Of Tech Geekers Incompetence: Emacs whitespace-mode
Xah Lee wrote: This feature is important in practical ways. For example, when you work with “tab separated line” files (CSV) that's a common format for importing/exporting address books or spreadsheets. CSV stands for comma separated values and the import facilities of any spreadsheet application lets the user define the field separator character. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: If Scheme is so good why MIT drops it?
fft1976 wrote: How do you explain that something as inferior as Python beat Lisp in the market place despite starting 40 years later. Probably due to similar reasons that lead php to become remotely relevant. Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Re: Is this a good time to start learning python?
After reading all replies I've decided to keep the subscription to this group, crank up the tutorials and start getting my head around Python. Thanks for all the helpful replies. Kudos, everyone! Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
Is this a good time to start learning python?
Recently I woke up inclined to take up the task of learning another programming language. I've already dipped my toes in Perl (I've read online tutorials and wrote a couple of irrelevant pet projects) but, as the computers at my workplace only sport the python interpreter, it probably means that learning python will end up serving me better, at least in the short run. Plus, you know how Perl goes. So far the decision seems to be a no brainer. Yet, Python 3000 will arrive in a few months. As it isn't backwards compatible with today's Python, there is the risk that no matter what I learn until then, I will end up having to re-learn at least a considerable part of the language. To put it in other words, I fear that I will be wasting my time. At least that is what a clueless newbie believes. As this group is frequented by people who have more insight into all things pythonesque, what are your thoughts on this? Thanks for the help Rui Maciel -- http://mail.python.org/mailman/listinfo/python-list
