Re: ten small Python programs
In article [EMAIL PROTECTED], Steve Howell [EMAIL PROTECTED] wrote: I've always thought that the best way to introduce new programmers to Python is to show them small code examples. Something like this: http://www.lava.se/sam/ Jacob Hallén -- -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Secondly, Python is nowadays not only used by programmers, but also by e.g. Scientific users (former MatLab users), who are not interested in the code itself, but just in the results of that particular code. For these people a lot of example programs, for which they can easily see the results, make some small changes and see the result again, would be a wonderful addition. In your own personal use, what are some libraries/techniques/etc. that you think could benefit from some kind of more organized presentation of example programs (or better way of showing how the examples work, etc.)? for example SciPy, but I think it yield for all libs/techniques. And I guess Windows users have a much greater need for such an organization than *nix users. Are you part of the Scientific community? sort of, I indeed work at a university, but not doing scientific work myself, I work on a supporting department. How new are you to Python? very new ;-) (I've lot of experience in a other programming languages, last years mostly Delphi, JAL, MatLab) I do think newbies/intermediates/advanceds all have different needs. agreed. cheers, Stef Mientki -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steve Howell wrote: I've always thought that the best way to introduce new programmers to Python is to show them small code examples. This is really a nice piece of missing Python. Sorry I didn't follow this thread accurately, but have you considered to produce an example environment like in wxPython ? The wxPython demo program is written as an interactive tutorial, with a few hundred examples, nicely ordered in groups. The user can view the demo, the code and the help text. The user can also change the code and see the results right away. It would even be nicer, if everybody could drop her/his examples in a standard way, so they would be automatically incorporated in something like the wxPython interactive demo. cheers, Stef Mientki -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Just for the amusement of the audience. The following is a reusable testscript: def add_money(amounts): ... pennies = sum([round(int(amount * 100)) for amount in amounts]) ... return float(pennies / 100.0) ... add_money([0.13, 0.02]) == 0.15 0.14999 add_money([0.13, 0.02]) == 0.15 True assert add_money([0.13, 0.02]) == 0.15 assert add_money([100.01, 99.99]) == 200 assert add_money([0, -13.00, 13.00]) == 0 It's just a matter of perspective... http://fiber-space.de/EasyExtend/doc/consoletest/consoletest.html -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Stef Mientki [EMAIL PROTECTED] wrote: Steve Howell wrote: I've always thought that the best way to introduce new programmers to Python is to show them small code examples. This is really a nice piece of missing Python. Thanks. The wxPython demo program is written as an interactive tutorial, with a few hundred examples, nicely ordered in groups. The user can view the demo, the code and the help text. The user can also change the code and see the results right away. Do you have a link? It would even be nicer, if everybody could drop her/his examples in a standard way, so they would be automatically incorporated in something like the wxPython interactive demo. Can you elaborate? 8:00? 8:25? 8:40? Find a flick in no time with the Yahoo! Search movie showtime shortcut. http://tools.search.yahoo.com/shortcuts/#news -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
The wxPython demo program is written as an interactive tutorial, with a few hundred examples, nicely ordered in groups. The user can view the demo, the code and the help text. The user can also change the code and see the results right away. Do you have a link? wxPython including demos can be downloaded from http://www.wxpython.org but there's no separate page of the demo, so I made a few screenshots: http://oase.uci.kun.nl/~mientki/data_www/pic/jalcc/python/wxpython_overview.html It would even be nicer, if everybody could drop her/his examples in a standard way, so they would be automatically incorporated in something like the wxPython interactive demo. Can you elaborate? Well if you see the above demo, I've the following in mind: - create a new-demo in a special directory - add some special keywords in the new-demo, in which treenodes it should popup - on restart of the demo, the new-demo is added to the tree cheers, Stef Mientki -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Stef Mientki [EMAIL PROTECTED] wrote: It would even be nicer, if everybody could drop her/his examples in a standard way, so they would be automatically incorporated in something like the wxPython interactive demo. Can you elaborate? Well if you see the above demo, I've the following in mind: - create a new-demo in a special directory - add some special keywords in the new-demo, in which treenodes it should popup - on restart of the demo, the new-demo is added to the tree To the extent that you just want a group of people to be able to organically organize a tree-like collection of Python examples, you could use a MoinMoin that has sensible page names and the Local Site Map featured turn on. Are you also suggesting the need for something local, so that you can actually run the programs? Luggage? GPS? Comic books? Check out fitting gifts for grads at Yahoo! Search http://search.yahoo.com/search?fr=oni_on_mailp=graduation+giftscs=bz -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steve Howell wrote: --- Stef Mientki [EMAIL PROTECTED] wrote: It would even be nicer, if everybody could drop her/his examples in a standard way, so they would be automatically incorporated in something like the wxPython interactive demo. Can you elaborate? Well if you see the above demo, I've the following in mind: - create a new-demo in a special directory - add some special keywords in the new-demo, in which treenodes it should popup - on restart of the demo, the new-demo is added to the tree To the extent that you just want a group of people to be able to organically organize a tree-like collection of Python examples, you could use a MoinMoin that has sensible page names and the Local Site Map featured turn on. Are you also suggesting the need for something local, so that you can actually run the programs? I don't know MoinMoin, but the answer is Yes (although maybe not for your ten snippets). First of all I think all programmers keep there own collection of code snippets, which much more valuable then all the code code snippets from everyone. Secondly, Python is nowadays not only used by programmers, but also by e.g. Scientific users (former MatLab users), who are not interested in the code itself, but just in the results of that particular code. For these people a lot of example programs, for which they can easily see the results, make some small changes and see the result again, would be a wonderful addition. just my 2 cents, cheers, Stef Mientki -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Stef Mientki [EMAIL PROTECTED] I don't know MoinMoin, but the answer is Yes (although maybe not for your ten snippets). First of all I think all programmers keep there own collection of code snippets, which much more valuable then all the code code snippets from everyone. Agreed. Secondly, Python is nowadays not only used by programmers, but also by e.g. Scientific users (former MatLab users), who are not interested in the code itself, but just in the results of that particular code. For these people a lot of example programs, for which they can easily see the results, make some small changes and see the result again, would be a wonderful addition. In your own personal use, what are some libraries/techniques/etc. that you think could benefit from some kind of more organized presentation of example programs (or better way of showing how the examples work, etc.)? Are you part of the Scientific community? How new are you to Python? I do think newbies/intermediates/advanceds all have different needs. Building a website is a piece of cake. Yahoo! Small Business gives you all the tools to get online. http://smallbusiness.yahoo.com/webhosting -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
On Sat, 26 May 2007 18:48:45 -0700, Steve Howell wrote: It also has a ComplexNumber class, but I don't want to scare away mathphobes. Is it as short as this one-liner? ComplexNumber = complex -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Steven D'Aprano [EMAIL PROTECTED] wrote: On Sat, 26 May 2007 18:48:45 -0700, Steve Howell wrote: It also has a ComplexNumber class, but I don't want to scare away mathphobes. Is it as short as this one-liner? ComplexNumber = complex The It above refers to *the* Python Tutorial, written by Guido van Rossum. Here is an excerpt: class Complex: ... def __init__(self, realpart, imagpart): ... self.r = realpart ... self.i = imagpart ... x = Complex(3.0, -4.5) x.r, x.i (3.0, -4.5) Obviously, it's not surprising that a useful class in a tutorial would have a corresponding implementation in the standard library, but I'm not sure newbies would learn much about classes from this statement: ComplexNumber = complex Need Mail bonding? Go to the Yahoo! Mail QA for great tips from Yahoo! Answers users. http://answers.yahoo.com/dir/?link=listsid=396546091 -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Steven D'Aprano wrote: On Sat, 26 May 2007 18:48:45 -0700, Steve Howell wrote: It also has a ComplexNumber class, but I don't want to scare away mathphobes. Is it as short as this one-liner? ComplexNumber = complex Along the idea of not reinventing a class from the standard library in the list of ten small Python programs (which has since grown), I went with the classic BankAccount example for the first program to introduce the class statement. You can see the code here: http://wiki.python.org/moin/SimplePrograms Be a better Globetrotter. Get better travel answers from someone who knows. Yahoo! Answers - Check it out. http://answers.yahoo.com/dir/?link=listsid=396545469 -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
On May 26, 1:43 pm, Steve Howell [EMAIL PROTECTED] wrote: -- parentRabbits, babyRabbits = (1, 1) while babyRabbits 100: print 'This generation has %d rabbits' % babyRabbits parentRabbits, babyRabbits = (babyRabbits, parentRabbits + babyRabbits) -- # def defines a method in Python def tax(itemCharge, taxRate = 0.05): return itemCharge * taxRate print '%.2f' % tax(11.35) print '%.2f' % tax(40.00, 0.08) For the person new to programming (doesn't come from C or other languages), I think you need to add a separate explanation of string formatting and how it works, or at least add a comment that tells them you are using string formatting so that they can search and find out how it works. If your aim is to teach simple programming concepts, why confuse them so early on with fancy interpolation? Something like # uses Python string formatting # http://docs.python.org/lib/typesseq-strings.html but really I think it will just be a distraction rd -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- BartlebyScrivener [EMAIL PROTECTED] wrote:
On May 26, 1:43 pm, Steve Howell
[EMAIL PROTECTED] wrote:
--
# def defines a method in Python
def tax(itemCharge, taxRate = 0.05):
return itemCharge * taxRate
print '%.2f' % tax(11.35)
print '%.2f' % tax(40.00, 0.08)
I decided to go with a simpler example up front.
--
# def defines a method in Python
def say_hello(name):
print 'hello', name
say_hello('Jack')
say_hello('Jill')
More here:
http://wiki.python.org/moin/SimplePrograms
Somebody also fixed a few style things in my other
examples, changing a tuple to a list, catching a more
specific exception. Whoever you are, thanks, I agree.
Sick
sense of humor? Visit Yahoo! TV's
Comedy with an Edge to see what's on, when.
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Re: ten small Python programs
--- BartlebyScrivener [EMAIL PROTECTED] wrote: For the person new to programming (doesn't come from C or other languages), I think you need to add a separate explanation of string formatting and how it works, or at least add a comment that tells them you are using string formatting so that they can search and find out how it works. If your aim is to teach simple programming concepts, why confuse them so early on with fancy interpolation? It's a thought provoking question, and I think my aim here is not exactly to teach simple programming concepts, but more to expose people to what Python looks like. I'm not really intending this page to be a tutorial, as several good tutorials already exist. I'm really targeting a particular niche of people. There are folks that know how to program, but don't know anything about Python, and they really just want to see a bunch of small examples all in one place, without a lot of explanation cluttering their presentation. That may sound like I'm narrowing my audience too much, but I do think it's a niche group that's not adequately addressed. I do hope, though, that folks more in a teaching role can reuse the examples, add better explanation, etc., as needed. Also, I wouldn't mind at all to add a little link called Read more... after each example. Ready for the edge of your seat? Check out tonight's top picks on Yahoo! TV. http://tv.yahoo.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steve Howell wrote:
# def defines a method in Python
def say_hello(name):
print 'hello', name
say_hello('Jack')
say_hello('Jill')
Doesn't def define methods *xor* functions, depending on the context?
And in this example, say_hello (*yuck*, underscores ...) is certainly a
function. Or is it that functions are considered module-methods?
W
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Re: ten small Python programs
--- Wildemar Wildenburger [EMAIL PROTECTED]
wrote:
Steve Howell wrote:
# def defines a method in Python
def say_hello(name):
print 'hello', name
say_hello('Jack')
say_hello('Jill')
Doesn't def define methods *xor* functions,
depending on the context?
And in this example, say_hello (*yuck*, underscores
...) is certainly a
function. Or is it that functions are considered
module-methods?
Goodness, I didn't expect such a simple example to be
so controversial. But please see the new version
here:
http://wiki.python.org/moin/SimplePrograms
I changed the method name to greet and removed the
comment, as hopefully the intent of the program will
be pretty obvious to anyone that reads it.
Luggage?
GPS? Comic books?
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Re: ten small Python programs
Steve Howell wrote: --- Steven Bethard [EMAIL PROTECTED] wrote: Very cool! Do you mind putting this up on the Wiki somewhere so that we can link to it more easily? Maybe something like: http://wiki.python.org/moin/SimplePrograms Done. I think I would rewrite the current unit-testing example to use the standard library unittest module:: # Let's write reusable code, and unit test it. def add_money(amounts): # do arithmetic in pennies so as not to accumulate float errors pennies = sum([round(int(amount * 100)) for amount in amounts]) return float(pennies / 100.0) import unittest class TestAddMoney(unittest.TestCase): def test_float_errors(self): self.failUnlessEqual(add_money([0.13, 0.02]), 0.15) self.failUnlessEqual(add_money([100.01, 99.99]), 200) self.failUnlessEqual(add_money([0, -13.00, 13.00]), 0) if __name__ == '__main__': unittest.main() I believe I've still kept it to 13 lines. STeVe P.S. The right way to add money is using the decimal module, but I couldn't think of a better example. -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Steven Bethard [EMAIL PROTECTED] wrote: I think I would rewrite the current unit-testing example to use the standard library unittest module:: # Let's write reusable code, and unit test it. def add_money(amounts): # do arithmetic in pennies so as not to accumulate float errors pennies = sum([round(int(amount * 100)) for amount in amounts]) return float(pennies / 100.0) import unittest class TestAddMoney(unittest.TestCase): def test_float_errors(self): self.failUnlessEqual(add_money([0.13, 0.02]), 0.15) self.failUnlessEqual(add_money([100.01, 99.99]), 200) self.failUnlessEqual(add_money([0, -13.00, 13.00]), 0) if __name__ == '__main__': unittest.main() I believe I've still kept it to 13 lines. I approve this change, although in a sense, it's harder for a Python newbie, because it introduces inheritance a little earlier than I would have liked. FWIW I'm in the minority (I think) of people that prefer roll-your-own testing, but I don't want to argue that, because I think it mostly comes down to personal preference. I'll only defend my position by posting this link, which suggests that roll-your-own even has validity in an educational setting: http://www.elkner.net/jeff/testFirst/index.html P.S. The right way to add money is using the decimal module, but I couldn't think of a better example. Agreed. Maybe somebody else will come up with something more creative, but I'm happy enough with our current version. Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos more. http://mobile.yahoo.com/go?refer=1GNXIC -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Steven Bethard [EMAIL PROTECTED] wrote: I think I would rewrite the current unit-testing example to use the standard library unittest module:: # Let's write reusable code, and unit test it. def add_money(amounts): # do arithmetic in pennies so as not to accumulate float errors pennies = sum([round(int(amount * 100)) for amount in amounts]) return float(pennies / 100.0) import unittest class TestAddMoney(unittest.TestCase): def test_float_errors(self): self.failUnlessEqual(add_money([0.13, 0.02]), 0.15) self.failUnlessEqual(add_money([100.01, 99.99]), 200) self.failUnlessEqual(add_money([0, -13.00, 13.00]), 0) if __name__ == '__main__': unittest.main() Just a minor quibble, but wouldn't you want the import and test class to only get executed in the ___main__ context? Got a little couch potato? Check out fun summer activities for kids. http://search.yahoo.com/search?fr=oni_on_mailp=summer+activities+for+kidscs=bz -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steve Howell wrote: --- Steven Bethard [EMAIL PROTECTED] wrote: I think I would rewrite the current unit-testing example to use the standard library unittest module:: # Let's write reusable code, and unit test it. def add_money(amounts): # do arithmetic in pennies so as not to accumulate float errors pennies = sum([round(int(amount * 100)) for amount in amounts]) return float(pennies / 100.0) import unittest class TestAddMoney(unittest.TestCase): def test_float_errors(self): self.failUnlessEqual(add_money([0.13, 0.02]), 0.15) self.failUnlessEqual(add_money([100.01, 99.99]), 200) self.failUnlessEqual(add_money([0, -13.00, 13.00]), 0) if __name__ == '__main__': unittest.main() Just a minor quibble, but wouldn't you want the import and test class to only get executed in the ___main__ context? That would be fine too. In the real world, I'd put the tests in a different module. STeVe -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steve Howell wrote: --- Steven Bethard [EMAIL PROTECTED] wrote: I think I would rewrite the current unit-testing example to use the standard library unittest module:: # Let's write reusable code, and unit test it. def add_money(amounts): # do arithmetic in pennies so as not to accumulate float errors pennies = sum([round(int(amount * 100)) for amount in amounts]) return float(pennies / 100.0) import unittest class TestAddMoney(unittest.TestCase): def test_float_errors(self): self.failUnlessEqual(add_money([0.13, 0.02]), 0.15) self.failUnlessEqual(add_money([100.01, 99.99]), 200) self.failUnlessEqual(add_money([0, -13.00, 13.00]), 0) if __name__ == '__main__': unittest.main() I believe I've still kept it to 13 lines. I approve this change, although in a sense, it's harder for a Python newbie, because it introduces inheritance a little earlier than I would have liked. FWIW I'm in the minority (I think) of people that prefer roll-your-own testing, but I don't want to argue that, because I think it mostly comes down to personal preference. Have you tried py.test? http://codespeak.net/py/dist/test.html I've heard good things about it, but haven't gotten around to trying it yet. Here's a two-line test suite from the page above: def test_answer(): assert 42 == 43 STeVe -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Steven Bethard [EMAIL PROTECTED] wrote: Steve Howell wrote: --- Steven Bethard [EMAIL PROTECTED] wrote: I think I would rewrite the current unit-testing example to use the standard library unittest module:: # Let's write reusable code, and unit test it. def add_money(amounts): # do arithmetic in pennies so as not to accumulate float errors pennies = sum([round(int(amount * 100)) for amount in amounts]) return float(pennies / 100.0) import unittest class TestAddMoney(unittest.TestCase): def test_float_errors(self): self.failUnlessEqual(add_money([0.13, 0.02]), 0.15) self.failUnlessEqual(add_money([100.01, 99.99]), 200) self.failUnlessEqual(add_money([0, -13.00, 13.00]), 0) if __name__ == '__main__': unittest.main() Just a minor quibble, but wouldn't you want the import and test class to only get executed in the ___main__ context? That would be fine too. In the real world, I'd put the tests in a different module. Maybe this is the first good example that motivates a hyperlink to alternatives. Would you accept the idea that we keep my original example on the SimplePrograms page, but we link to a UnitTestingPhilosophies page, and we show your alternative there? Or vice versa, show your example on the first page, but then show mine on the hyperlinked page? I am in 100% agreement with you that most unit tests would be completely outside the module, although I often follow the practice that my modules have a little if __main__ section that runs a few simple unit tests, as sort of a bit of self-documentation. Building a website is a piece of cake. Yahoo! Small Business gives you all the tools to get online. http://smallbusiness.yahoo.com/webhosting -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steve Howell wrote: --- Steven Bethard [EMAIL PROTECTED] wrote: Steve Howell wrote: --- Steven Bethard [EMAIL PROTECTED] wrote: I think I would rewrite the current unit-testing example to use the standard library unittest module:: # Let's write reusable code, and unit test it. def add_money(amounts): # do arithmetic in pennies so as not to accumulate float errors pennies = sum([round(int(amount * 100)) for amount in amounts]) return float(pennies / 100.0) import unittest class TestAddMoney(unittest.TestCase): def test_float_errors(self): self.failUnlessEqual(add_money([0.13, 0.02]), 0.15) self.failUnlessEqual(add_money([100.01, 99.99]), 200) self.failUnlessEqual(add_money([0, -13.00, 13.00]), 0) if __name__ == '__main__': unittest.main() Just a minor quibble, but wouldn't you want the import and test class to only get executed in the ___main__ context? That would be fine too. In the real world, I'd put the tests in a different module. Maybe this is the first good example that motivates a hyperlink to alternatives. Would you accept the idea that we keep my original example on the SimplePrograms page, but we link to a UnitTestingPhilosophies page, and we show your alternative there? Or vice versa, show your example on the first page, but then show mine on the hyperlinked page? Sure. Either way is fine. STeVe -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Steven Bethard [EMAIL PROTECTED] wrote: Maybe this is the first good example that motivates a hyperlink to alternatives. Would you accept the idea that we keep my original example on the SimplePrograms page, but we link to a UnitTestingPhilosophies page, and we show your alternative there? Or vice versa, show your example on the first page, but then show mine on the hyperlinked page? Sure. Either way is fine. Ok, for now, I'm taking no action, let's let the unit testing discussion progress a little. Despite my saying early that I don't want to debate it, I do want to discuss it :), as it is near in dear to my heart. Yahoo! oneSearch: Finally, mobile search that gives answers, not web links. http://mobile.yahoo.com/mobileweb/onesearch?refer=1ONXIC -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steven Bethard [EMAIL PROTECTED] writes: I think I would rewrite the current unit-testing example to use the standard library unittest module:: I think these days we're supposed to like doctest better than unittest. -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steve Howell wrote: I've always thought that the best way to introduce new programmers to Python is to show them small code examples. snip You could try this wiki page: http://rosettacode.org/wiki/Main_Page It has a fair amount of Python examples as well as many more other languages (doing the same algorithm). Hope this helps. Adonis -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
You could try this wiki page: http://rosettacode.org/wiki/Main_Page It has a fair amount of Python examples as well as many more other languages (doing the same algorithm). Hope this helps. Adonis THIS IS GREAT :) Thanx! -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
On 11:43 Sat 26 May , Steve Howell wrote: I've always thought that the best way to introduce new programmers to Python is to show them small code examples. When you go to the tutorial, though, you have to wade through quite a bit of English before seeing any Python examples. Below is my attempt at generating ten fairly simple, representative Python programs that expose new users to most basic concepts, as well as the overall syntax. It was an interesting exercise. I constrained myself to ten lines or less, and it was pretty easy to incorporate loops, conditionals, print, open(), lists, tuples, dictionaries, and imported modules. It was harder to show classes, and my ShoppingCart class is nothing more than an encapsulation of a list, which has dubious value (although it's the start of something more useful). Anyway, here goes: Many thanks for that. This is exactly what is missing in most introductory books. Simple, relevant and concise examples. Regards, John -- War is God's way of teaching Americans geography Ambrose Bierce (1842 - 1914) -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Steve Howell wrote:
I've always thought that the best way to introduce new
programmers to Python is to show them small code
examples.
When you go to the tutorial, though, you have to wade
through quite a bit of English before seeing any
Python examples.
Below is my attempt at generating ten fairly simple,
representative Python programs that expose new users
to most basic concepts, as well as the overall syntax.
Very cool! Do you mind putting this up on the Wiki somewhere so that we
can link to it more easily? Maybe something like:
http://wiki.python.org/moin/SimplePrograms
nitpick
Though the code should probably follow PEP 8 guidelines, e.g.
under_scores instead of camelCase for object and method names:
http://www.python.org/dev/peps/pep-0008/
/nitpick
class ShoppingCart:
def __init__(self): self.items = []
def buy(self, item): self.items.append(item)
def boughtItems(self): return self.items
myCart = ShoppingCart()
myCart.buy('apple')
myCart.buy('banana')
print myCart.boughtItems()
I think boughtItems() is probably not a good example of Python code
since in this case, you should probably just write ``my_cart.items``.
Maybe it should define ``__len__`` instead? Or maybe something like::
def select_items(self, prefix):
return [item for item in self.items if item.startswith(prefix)]
STeVe
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Re: ten small Python programs
--- Steven Bethard [EMAIL PROTECTED] wrote:
Very cool! Do you mind putting this up on the Wiki
somewhere so that we
can link to it more easily? Maybe something like:
http://wiki.python.org/moin/SimplePrograms
Done.
nitpick
Though the code should probably follow PEP 8
guidelines, e.g.
under_scores instead of camelCase for object and
method names:
http://www.python.org/dev/peps/pep-0008/
/nitpick
I think I fixed them, please see Wiki to verify.
class ShoppingCart:
def __init__(self): self.items = []
def buy(self, item):
self.items.append(item)
def boughtItems(self): return self.items
myCart = ShoppingCart()
myCart.buy('apple')
myCart.buy('banana')
print myCart.boughtItems()
I think boughtItems() is probably not a good example
of Python code
since in this case, you should probably just write
``my_cart.items``.
Maybe it should define ``__len__`` instead? Or maybe
something like::
def select_items(self, prefix):
return [item for item in self.items if
item.startswith(prefix)]
I think the problem here is that it's hard to write a
useful class in less than 10 lines of code. Can
somebody else give it a try?
Although I didn't call it out in the email, I tried to
make each program progressively one line longer, so if
somebody wants to write, say, an 11-line class
example, then I will try fill in the gap with another
8-liner.
Did I miss any basic concepts in the first 10
programs? Maybe an 8-liner could demonstrate command
line arguments?
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Re: ten small Python programs
I ***love*** this 10 Little Programs idea! As soon as I get a
breathing space, I'm going to add a 10 Little Parsers page to the
pyparsing wiki!
On May 26, 2:38 pm, Steven Bethard [EMAIL PROTECTED] wrote:
nitpick
Though the code should probably follow PEP 8 guidelines, e.g.
under_scores instead of camelCase for object and method names:
http://www.python.org/dev/peps/pep-0008/
/nitpick
Really? Underscore-separated words preferred over camel case? What
is the rationale for this? This style is so retro/80's/C-ish. It
seems more like a Java backlash to me than anything else. If we (or
Guido) don't like changing case to indicate word breaks, why are class
names to be UpperCamelCase, and not Capitalized_with_underscores? If
there is a casing convention nit to pick, I'd focus on UpperCamelCase
for class names, lower case (either with underscores or mixed case)
for attributes and method names, and UNDERSCORE_SEPARATED_ALL_CAPS for
constants.
If we want to just say well, PEP-8 says such and such, I think this
is an area where the thinking has possibly evolved since 2001. Also,
I think the PEP would benefit from explicitly discouraging some
practices, such as Hungarian notation.
class ShoppingCart:
def __init__(self): self.items = []
def buy(self, item): self.items.append(item)
def boughtItems(self): return self.items
myCart = ShoppingCart()
myCart.buy('apple')
myCart.buy('banana')
print myCart.boughtItems()
If you want to nitpick, I'd rather go after the one-liner methods with
the body on the same line as the def statement.
How's this for a better non-trivial method example:
MAX_ITEMS_FOR_EXPRESS_LANE = 10
def canUseExpressLane(self):
return (len(self.items) = MAX_ITEMS_FOR_EXPRESS_LANE)
or call it can_use_express_lane if you must.
I guess pyparsing with its mixedCase functions and attributes is
doomed for the Dunce Corner. Too bad for BeautifulSoup, cElementTree,
and wxPython that are also at variance with this canon of Python
coding style. (Modules should have short, all-lowercase names. ...
Python packages should also have short, all-lowercase names, although
the use of underscores is discouraged.)
-- Paul
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Re: ten small Python programs
Paul McGuire wrote: [...]. I guess pyparsing with its mixedCase functions and attributes is doomed for the Dunce Corner. Too bad for BeautifulSoup, cElementTree, and wxPython that are also at variance with this canon of Python coding style. (Modules should have short, all-lowercase names. ... Python packages should also have short, all-lowercase names, although the use of underscores is discouraged.) Although the names in wxPython are indeed contrary to PEP 8 (because they are the same as the names used in wxWidgets) I should point out that nowadays the name you import is wx. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC/Ltd http://www.holdenweb.com Skype: holdenweb http://del.icio.us/steve.holden -- Asciimercial - Get on the web: Blog, lens and tag your way to fame!! holdenweb.blogspot.comsquidoo.com/pythonology tagged items: del.icio.us/steve.holden/python All these services currently offer free registration! -- Thank You for Reading -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Paul McGuire [EMAIL PROTECTED] wrote:
I ***love*** this 10 Little Programs idea! As
soon as I get a
breathing space, I'm going to add a 10 Little
Parsers page to the
pyparsing wiki!
Thanks. :)
I'm thinking you could actually have a progression
from a 1 line program up to a 50-line program. The
number 50 is kind of arbitrary, but my gut says that
by a 50-line program, you will have demonstrated
almost every useful concept.
class ShoppingCart:
def __init__(self): self.items = []
def buy(self, item):
self.items.append(item)
def boughtItems(self): return self.items
myCart = ShoppingCart()
myCart.buy('apple')
myCart.buy('banana')
print myCart.boughtItems()
If you want to nitpick, I'd rather go after the
one-liner methods with
the body on the same line as the def statement.
Agreed. I didn't like that either.
How's this for a better non-trivial method example:
MAX_ITEMS_FOR_EXPRESS_LANE = 10
def canUseExpressLane(self):
return (len(self.items) =
MAX_ITEMS_FOR_EXPRESS_LANE)
or call it can_use_express_lane if you must.
Yep, that sounds more in the ballpark of what I'd want
to show, versus a weakish class that just encapulates
a list.
Here's my challenge to whoever wants to take it--write
(or find) a program with 20 or fewer lines that
sufficiently motivates the need for classes, has
decent Python style, and is newbie friendly.
The tutorial has this example, which is useful for
demonstrating the syntax of classes, but it doesn't
actually do anything interesting:
class MyClass:
A simple example class
i = 12345
def f(self):
return 'hello world'
It also has a ComplexNumber class, but I don't want to
scare away mathphobes.
It does have this idiom, which I think is worth
putting somewhere into the progression.
class Employee:
pass
john = Employee() # Create an empty employee record
# Fill the fields of the record
john.name = 'John Doe'
john.dept = 'computer lab'
john.salary = 1000
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Re: ten small Python programs
On May 26, 8:48 pm, Steve Howell [EMAIL PROTECTED] wrote: I'm thinking you could actually have a progression from a 1 line program up to a 50-line program. The number 50 is kind of arbitrary, but my gut says that by a 50-line program, you will have demonstrated almost every useful concept. If there is anything arbitrary here, I'd say it is your increment each example by one source line constraint. This can force you to use some bad coding practices to meet your target line count for a given example. Maybe try this approach: pick your top 10/20/50 language features and develop concise examples. Then order the examples by length as a first cut (longer examples probably *are* more complex), and then reorder a bit to handle pre-requisites (introduce a minimum of new features, preferably 1, per example). Overall, I'd have a tough time picking just 10 language features to illustrate, but there are probably 10-20 basic features that will get new people onto fairly productive ground. Pick 20 as your example count (50 sounds a bit long), and stick to it, and then later add 20 More Little Programs for the next wave of examples in increasing complexity. One other nit to pick: have your example classes inherit from object, to get new people using new-style classes from the get-go. -- Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Paul McGuire wrote: I ***love*** this 10 Little Programs idea! As soon as I get a breathing space, I'm going to add a 10 Little Parsers page to the pyparsing wiki! On May 26, 2:38 pm, Steven Bethard [EMAIL PROTECTED] wrote: nitpick Though the code should probably follow PEP 8 guidelines, e.g. under_scores instead of camelCase for object and method names: http://www.python.org/dev/peps/pep-0008/ /nitpick Really? Underscore-separated words preferred over camel case? What is the rationale for this? Rationale? It's a style guide. There is no rationale. ;-) If we want to just say well, PEP-8 says such and such, I think this is an area where the thinking has possibly evolved since 2001. I really don't think so. If anything, it's gotten more strict. PEP 8 used to allow either camelCase or under_scores. Now it only allows the latter. I guess pyparsing with its mixedCase functions and attributes is doomed for the Dunce Corner. Too bad for BeautifulSoup, cElementTree, and wxPython that are also at variance with this canon of Python coding style. Many (if not all) of these modules were written before the most recent incarnation of PEP 8. Thus, they fall under the second good reason to break a particular rule: (2) To be consistent with surrounding code that also breaks it Of course, for new code, such as that in this thread, there's no reason to break from the PEP 8 guidelines. STeVe -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
--- Paul McGuire [EMAIL PROTECTED] wrote: On May 26, 8:48 pm, Steve Howell [EMAIL PROTECTED] wrote: I'm thinking you could actually have a progression from a 1 line program up to a 50-line program. The number 50 is kind of arbitrary, but my gut says that by a 50-line program, you will have demonstrated almost every useful concept. If there is anything arbitrary here, I'd say it is your increment each example by one source line constraint. This can force you to use some bad coding practices to meet your target line count for a given example. I understand your point, but I'm sticking to the concept for now. My intent with the progression isn't so much for each example to thoroughly teach a concept (although I could certainly hyperlink to a more in-depth treatment), but really more to give a bird's eye view of the language very quickly. I recently helped teach a Java programmer to program in Python, and he learned a lot just by seeing simple examples. So I guess my target audience isn't so much people learning how to program; it's more for programmers getting their first exposure to Python. On the other side of the fence, I recently tried to relearn a bit of Ruby, and I remember being frustrated by their tutorials, as really, I just wanted to see a bunch of simple programs, and I can figure out mostly what they're doing. Instead, I had to wade through verbose descriptions of what a variable is, rules for how you construct identifiers, etc. Maybe try this approach: pick your top 10/20/50 language features and develop concise examples. Then order the examples by length as a first cut (longer examples probably *are* more complex), and then reorder a bit to handle pre-requisites (introduce a minimum of new features, preferably 1, per example). Overall, I'd have a tough time picking just 10 language features to illustrate, but there are probably 10-20 basic features that will get new people onto fairly productive ground. Pick 20 as your example count (50 sounds a bit long), and stick to it, and then later add 20 More Little Programs for the next wave of examples in increasing complexity. My only reluctance with that approach is that it sounds like a little more work than I'm ready to take on right away. But it's on the Wiki now, so maybe other folks can help me grow it. One other nit to pick: have your example classes inherit from object, to get new people using new-style classes from the get-go. My only fear here is that when old classes go away (Py3K? I don't know), that practice may become obsolete. But on a more general note, I welcome folks to just clean up my examples on the Wiki if I accidentally introduce some bad practices...but preserving line counts. :) Never miss an email again! Yahoo! Toolbar alerts you the instant new Mail arrives. http://tools.search.yahoo.com/toolbar/features/mail/ -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
Out of curiosity, how does this style jibe with the latest embracing of Unicode identifiers? Ever tried to type an underscore on a non-US keyboard? I have a heck of a time finding/typing the '_' character when I visit our clients in Germany, but this may just be my own personal Amerocentric issue (I also get messed up by the transposition of Y and Z on German keyboards, but my German colleagues understandably are not bothered by it). For someone already familiar with that keyboard layout, is typing an underscore any more difficult than my pressing Shift-_ on my US keyboard? -- Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: ten small Python programs
On May 26, 9:58 pm, Paul McGuire [EMAIL PROTECTED] wrote: Out of curiosity, how does this style jibe with the latest embracing of Unicode identifiers? Ever tried to type an underscore on a non-US keyboard? I have a heck of a time finding/typing the '_' character when I visit our clients in Germany, but this may just be my own personal Amerocentric issue (I also get messed up by the transposition of Y and Z on German keyboards, but my German colleagues understandably are not bothered by it). For someone already familiar with that keyboard layout, is typing an underscore any more difficult than my pressing Shift-_ on my US keyboard? -- Paul Steve, sorry for going so far off-topic. I've started a new thread on my questions about this aspect of PEP-8, and if there's more to say about this, people should post it there. -- Paul -- http://mail.python.org/mailman/listinfo/python-list
