Is using range() in for loops really Pythonic?

[John Nagle]

Re: Is using range() in for loops really Pythonic?

Matt Nordhoff wrote:

John Salerno wrote:

>I know it's popular and very handy, but I'm curious if there are purists
>out there who think that using something like:
>>
>for x in range(10):
> #do something 10 times
>>
>is unPythonic. The reason I ask is because the structure of the for loop
>seems to be for iterating through a sequence. It seems somewhat
>artificial to use the for loop to do something a certain number of
>times, like above.
>>
>Anyone out there refuse to use it this way, or is it just impossible to
>avoid?

>
Well, you should use "xrange(10) " instead of "range(10)" .

CPython really is naive. That sort of thing should be a
compile-time optimization.

John Nagle

[Ben Finney]

Re: Is using range() in for loops really Pythonic?

John Nagle <nagle@animats. comwrites:

Matt Nordhoff wrote:

Well, you should use "xrange(10) " instead of "range(10)" .

>
CPython really is naive. That sort of thing should be a
compile-time optimization.

Or even a case of the 'xrange' behaviour making 'range' obsolete.

Which, as I pointed out earlier in the thread, it is in Python 3.0.

--
\ "Yesterday I parked my car in a tow-away zone. When I came back |
`\ the entire area was missing." -- Steven Wright |
_o__) |
Ben Finney

[Marc 'BlackJack' Rintsch]

Re: Is using range() in for loops really Pythonic?

On Tue, 13 May 2008 10:20:41 -0700, John Nagle wrote:

Matt Nordhoff wrote:
>

>Well, you should use "xrange(10) " instead of "range(10)" .

>
CPython really is naive. That sort of thing should be a
compile-time optimization.

It's not naive, it can't know at compile time what object is bound to the
name `xrange` at runtime.

Ciao,
Marc 'BlackJack' Rintsch

[cokofreedom@gmail.com]

Re: Is using range() in for loops really Pythonic?

On May 14, 8:37 am, Marc 'BlackJack' Rintsch <bj_...@gmx.net wrote:

On Tue, 13 May 2008 10:20:41 -0700, John Nagle wrote:

Matt Nordhoff wrote:

>

Well, you should use "xrange(10) " instead of "range(10)" .

>

CPython really is naive. That sort of thing should be a
compile-time optimization.

>
It's not naive, it can't know at compile time what object is bound to the
name `xrange` at runtime.
>
Ciao,
Marc 'BlackJack' Rintsch

I think he meant you should just use xrange over range at all times.

[Graham Breed]

Re: Is using range() in for loops really Pythonic?

George Sakkis wrote:

If you push this logic too far, you should del every name immediately
after the last statement it is used in the scope. I would generally
find less readable some code spread with del every few lines, micro-
managing the effective scope of each name. YMMV.

Yes, but ... how about

for i in range(10):
del i
do stuff

?

It makes it clear you aren't using the index and ensures you
get a run-time error if you clobbered an existing variable.


Graham

[Dave Parker]

Re: Is using range() in for loops really Pythonic?

Your point about for-loops was applicable not only to Python, but to
many other programming languages. So in response, I've added two new
for-loop variations to Flaming Thunder.

The two new variations are for-forever-do and for-expression-times-do.
For-forever allows you to explicitly create infinite loops, and for-
expression-times allows you to do something a specific number of times
without having to declare a looping variable if you don't need one.
Examples:

Write "Fa". For 8 times do write "-la".

For forever do
(
Write "Do you know the definition of insanity? ".
Read response.
).

On May 10, 8:19 pm, John Salerno <johnj...@NOSPA Mgmail.comwrote :

I know it's popular and very handy, but I'm curious if there are purists
out there who think that using something like:
>
for x in range(10):
    #do something 10 times
>
isunPythonic. The reason I ask is because the structure of the for loop
seems to be for iterating through a sequence. It seems somewhat
artificial to use the for loop to do something a certain number of
times, like above.
>
Anyone out there refuse to use it this way, or is it just impossible to
avoid?