Bragging about Python
pinkflo...@gmail.com
and effectively show Python's strengths to non-Python programmers?
Small examples that will make them go "Wow, that _is_ neat"?
Steve Howell
--- "pinkflo...@gmail.com"
<pinkflo...@gmail.com> wrote:
15 small programs here:
http://wiki.python.org/moin/SimplePrograms
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Mathias Panzenboeck
> --- "pinkflo...@gmail.com"
> <pinkflo...@gmail.com> wrote:
>
>> Is there a resource somewhere on the net that can be
>> used to quickly
>> and effectively show Python's strengths to
>> non-Python programmers?
>> Small examples that will make them go "Wow, that
>> _is_ neat"?
>>
>
> 15 small programs here:
>
> http://wiki.python.org/moin/SimplePrograms
>
IMHO a few python goodies are missing there.
e.g. generator functions:
# generic fibonacci without upper bound:
def fib():
parent_rabbits, baby_rabbits = 1, 1
while True:
yield baby_rabbits
parent_rabbits, baby_rabbits = baby_rabbits, parent_rabbits + baby_rabbits
# only calculate and print the first 100 fibonacci numbers:
from itertools import islice
for baby_rabbits in islice(fib(),100):
print 'This generation has %d rabbits' % baby_rabbits
Cameron Laird
Good point.
This example intrigues me. When I saw the first couple of lines,
I expected
def fib():
generation, parent_rabbits, baby_rabbits = 1, 1, 1
while True:
yield generation, baby_rabbits
generation += 1
parent_rabbits, baby_rabbits = \
baby_rabbits, parent_rabbits + baby_rabbits
for pair in fib():
if pair[0] > 100:
break
print "Generation %d has %d (baby) rabbits." % pair
as more appealing to non-Pythoneers. I'm still suspicious about
how they're going to react to itertools.islice(). Now, though,
I've begun to question my own sense of style ...
Georg Brandl
> Steve Howell schrieb:
>> --- "pinkflo...@gmail.com"
>> <pinkflo...@gmail.com> wrote:
>>
>>> Is there a resource somewhere on the net that can be
>>> used to quickly
>>> and effectively show Python's strengths to
>>> non-Python programmers?
>>> Small examples that will make them go "Wow, that
>>> _is_ neat"?
>>>
>>
>> 15 small programs here:
>>
>> http://wiki.python.org/moin/SimplePrograms
>>
>
> IMHO a few python goodies are missing there.
"It's a Wiki." ;)
Georg
--
Thus spake the Lord: Thou shalt indent with four spaces. No more, no less.
Four shall be the number of spaces thou shalt indent, and the number of thy
indenting shall be four. Eight shalt thou not indent, nor either indent thou
two, excepting that thou then proceed to four. Tabs are right out.
Szabolcs Nagy
actually i don't like when a tutorial uses over complicated cute names
if the context is obvious (fibonacci) then we don't need to add
'parent_rabbits' and such identifiers
eg i find more readable and clear the following:
def fib():
a, b = 0, 1
while True:
yield a
a, b = b, a + b
for (n, fn) in enumerate(fib()):
if n > 100:
break
print "F[%d] = %d" % (n, fn)
ymmv
Steve Howell
--- Szabolcs Nagy <nsza...@gmail.com> wrote:
>
> actually i don't like when a tutorial uses over
> complicated cute names
> if the context is obvious (fibonacci) then we don't
> need to add
> 'parent_rabbits' and such identifiers
I still prefer the use of "rabbits," but I don't mind
if people change that, as I understand the brevity argument.
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Steve Howell
> def fib():
> generation, parent_rabbits, baby_rabbits = 1,
> 1, 1
> while True:
> yield generation, baby_rabbits
> generation += 1
> parent_rabbits, baby_rabbits = \
> baby_rabbits, parent_rabbits +
> baby_rabbits
>
> for pair in fib():
> if pair[0] > 100:
> break
> print "Generation %d has %d (baby) rabbits."
> % pair
>
One goal behind the SimplePrograms page is to give
people that are new to Python a *gentle* immersion
into Python code. I prefer simple:
parent_rabbits, baby_rabbits = (1, 1)
while baby_rabbits < 100:
print 'This generation has %d rabbits' %
baby_rabbits
parent_rabbits, baby_rabbits = (baby_rabbits,
parent_rabbits + baby_rabbits)
Somebody commented in another reply that they'd prefer
the variable names "a" and "b," but other than that, I
think it's hard to simplify this.
The problem of counting rabbits is not sufficiently
rich to motivate a solution with generator functions,
and "yield" statements are just gonna scare people
away from the Python, unless they've had a chance to
see simpler idioms first.
I do think there's a place on the page for a good
generators example, but it needs to solve a
sufficiently complex problem that the use of
generators actually simplifies the solution.
So I'm throwing down the gauntlet--can somebody write
a short program (maybe 10 to 20 lines) where you solve
a problem more simply than a similar
non-generator-using solution would solve it? Maybe
something like Eight Queens?
-- Steve
P.S. FWIW the page does already include examples of
generator expressions and the itertools module, but it
does not yet show any code that actually implements a
generator. I would greatly welcome the addition of a
good example.
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Steve Howell
> >>
> >> 15 small programs here:
> >>
> >> http://wiki.python.org/moin/SimplePrograms
> >>
> >
> > IMHO a few python goodies are missing there.
>
> "It's a Wiki." ;)
>
Yes indeed. Please feel free to add to the page, or
make your own fork. See link above.
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Szabolcs Nagy
Steve Howell wrote:
> --- Georg Brandl <g.br...@gmx.net> wrote:
> > >>
> > >> 15 small programs here:
> > >>
> > >> http://wiki.python.org/moin/SimplePrograms
> > >>
> > >
> > > IMHO a few python goodies are missing there.
> >
> > "It's a Wiki." ;)
> >
>
> Yes indeed. Please feel free to add to the page, or
> make your own fork. See link above.
the title of a program shouldn't be part of the code (or it should at
least start with #)
sorry i'm too lazy now to fix it, but imho it needs nicer layout to be
used as 'bragging about python' site
btw nice idea
a good example worth a 100 pages of documentation
Steve Howell
> (or it should at
> least start with #)
> sorry i'm too lazy now to fix it, but imho it needs
> nicer layout to be
> used as 'bragging about python' site
>
Agreed. I just spruced up the layout a tiny bit, but
it could still use improvement.
http://wiki.python.org/moin/SimplePrograms
> btw nice idea
> a good example worth a 100 pages of documentation
>
Thanks, I agree. :)
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Paul McGuire
> Yahoo! oneSearch: Finally, mobile search
>
> - Show quoted text -
Well, I misread your "gauntlet throwing", and implemented a brief 8-
queens using recursion and exceptions. Perhaps this could serve as
the "before" to an "after" using generators. (I note that neither
recursion nor exceptions are covered in your examples.) Also, in
googling about for other 8-queens solutions in Python, most are quite
complicated - this one uses only 24 lines, and works for boards of any
size. I also think this line for printing out the board:
print "\n".join( "."*q+"Q"+"."*(BOARD_SIZE-q-1) for q in queens )
illustrates a couple of interesting idioms of Python (joining a list,
generator expression, "."*repetition to give "....").
Worthy of your page?
-- Paul
BOARD_SIZE = 8
def validate(queens):
left = right = col = queens[-1]
for r in reversed(queens[:-1]):
left,right = left-1,right+1
if r in (left, col, right):
raise Exception
def add_queen(queens):
for i in range(BOARD_SIZE):
testQueens = queens+[i]
try:
validate(testQueens)
if len(testQueens)==BOARD_SIZE:
return testQueens
else:
return add_queen(testQueens)
except:
pass
raise Exception
queens = add_queen([])
print queens
print "\n".join( "."*q+"Q"+"."*(BOARD_SIZE-q-1) for q in queens )
Steve Howell
--- Paul McGuire <pt...@austin.rr.com> wrote:
> >
> > So I'm throwing down the gauntlet--can somebody
> write
> > a short program (maybe 10 to 20 lines) where you
> solve
> > a problem more simply than a similar
> > non-generator-using solution would solve it?
> Maybe
> > something like Eight Queens?
> >
>
> implemented a brief 8-
> queens using recursion and exceptions. Perhaps this
> could serve as
> the "before" to an "after" using generators. (I note
> that neither
> recursion nor exceptions are covered in your
> examples.)
Actually, there was a minor example with exceptions,
but agreed re:recursion, and this is just such a
classic problem, it belongs on the page.
> Also, in
> googling about for other 8-queens solutions in
> Python, most are quite
> complicated - this one uses only 24 lines, and works
> for boards of any
> size. I also think this line for printing out the
> board:
>
> print "\n".join( "."*q+"Q"+"."*(BOARD_SIZE-q-1) for
> q in queens )
>
> illustrates a couple of interesting idioms of Python
> (joining a list,
> generator expression, "."*repetition to give
> "....").
Agreed.
>
> Worthy of your page?
>
Definitely worthy. Go ahead and add it.
FWIW I have been labelling programs by the number of
lines of code. So this is program #24, which now
creates a gap between #16 and #23.
Also, I humbly suggest test_queens instead of
testQueens. I don't want to reopen the PEP 8 debate,
just a recommendation. I think PEP 8 would also
suggest some white space around '+' and '=='.
>
> BOARD_SIZE = 8
> def validate(queens):
> left = right = col = queens[-1]
> for r in reversed(queens[:-1]):
> left,right = left-1,right+1
> if r in (left, col, right):
> raise Exception
>
> def add_queen(queens):
> for i in range(BOARD_SIZE):
> testQueens = queens+[i]
> try:
> validate(testQueens)
> if len(testQueens)==BOARD_SIZE:
> return testQueens
> else:
> return add_queen(testQueens)
> except:
> pass
> raise Exception
>
> queens = add_queen([])
> print queens
> print "\n".join( "."*q+"Q"+"."*(BOARD_SIZE-q-1) for
> q in queens )
>
Very Pythonic solution IMHO. Nicely done.
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Richard Jones
> --- Szabolcs Nagy <nsza...@gmail.com> wrote:
>>
>> actually i don't like when a tutorial uses over
>> complicated cute names
>> if the context is obvious (fibonacci) then we don't
>> need to add
>> 'parent_rabbits' and such identifiers
>
> I still prefer the use of "rabbits," but I don't mind
> if people change that, as I understand the brevity argument.
The rabbit naming scheme makes the code far more accessible to people who
aren't as familiar with fibonacci.
Really, this is about making Python accessible to more people, not the same
people it's currently accessible to :)
Richard