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 infi

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

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

On May 14, 8:37 am, Marc 'BlackJack' Rintsch <[EMAIL PROTECTED]> 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-tim

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 b

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

John Nagle <[EMAIL PROTECTED]> writes: > 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 p

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 f

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

On May 13, 9:20 pm, Lie <[EMAIL PROTECTED]> wrote: > On May 13, 11:01 am, John Salerno <[EMAIL PROTECTED]> wrote: > > > > > Ben Finney wrote: > > > I think that the idiom > > > >     for unused in xrange(10): > > >         # do stuff with no reference to 'unused' > > > > is quite common. Is that wh

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

On May 13, 11:01 am, John Salerno <[EMAIL PROTECTED]> wrote: > Ben Finney wrote: > > I think that the idiom > > >     for unused in xrange(10): > >         # do stuff with no reference to 'unused' > > > is quite common. Is that what you're asking about? > > Yes. I was more or less asking about the

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

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

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

> REXX's loop construct subsumes all the common uses... And worse, it > appears that a repetition and a condition can be part of the single > statement. Thank you for pointing out the REXX examples. I am a Kedit user, but had forgotten about the REXX do-loops. I'll keep them in mind when

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

On Mon, 12 May 2008 11:23:07 -0700, Carl Banks wrote: > On May 12, 3:42 am, Ben Finney <[EMAIL PROTECTED]> > wrote: >> Because of the precedent of those names, choosing one of those names >> doesn't make it clear to the reader that the value is never used; > > > Why is it even necessary to docum

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

"John Salerno" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | The reason I even brought this up is because I remember someone saying a | while back (probably here on the newsgroup) that the true use of a for | loop was to iterate through a sequence (for the purpose of using that |

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

Ben Finney wrote: > I think that the idiom > > for unused in xrange(10): > # do stuff with no reference to 'unused' > > is quite common. Is that what you're asking about? Yes. I was more or less asking about the specific situation of using a for loop to do something X number of times,

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

On May 12, 7:03 pm, Ben Finney <[EMAIL PROTECTED]> wrote: > Carl Banks <[EMAIL PROTECTED]> writes: > > IMHO, whether a varibale is used or not has got to be one of the least > > important things of all (in no small part because it's easily > > discernable from nearby code). > > I couldn't disagree

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

On May 10, 8:19 pm, John Salerno <[EMAIL PROTECTED]> wrote: > It seems somewhat > artificial to use the for loop to do something a certain number of > times, like above. I agree; it's a common flaw with lots of languages, not just Python. I'd be inclined to use something like: FOR 8 TIMES DO .

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

"Ben Finney" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | So, when not using the values that come from the controlling iterator, | it's good to make that explicit. If Python supported it, we might | prefer to use no name at all for something that isn't used, but the | 'for' synta

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

On May 12, 7:03 pm, Ben Finney <[EMAIL PROTECTED]> wrote: > Carl Banks <[EMAIL PROTECTED]> writes: > > IMHO, whether a varibale is used or not has got to be one of the least > > important things of all (in no small part because it's easily > > discernable from nearby code). > > I couldn't disagree

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

Carl Banks <[EMAIL PROTECTED]> writes: > IMHO, whether a varibale is used or not has got to be one of the least > important things of all (in no small part because it's easily > discernable from nearby code). I couldn't disagree more. If you're binding a name to a value that will never be used,

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

On May 12, 3:42 am, Ben Finney <[EMAIL PROTECTED]> wrote: > Because of the precedent of those names, choosing one of those names > doesn't make it clear to the reader that the value is never used; Why is it even necessary to document this? This is the thing that baffles me the most about this th

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

On May 12, 3:46 pm, Grant Edwards <[EMAIL PROTECTED]> wrote: > On 2008-05-12, Ben Finney <[EMAIL PROTECTED]> wrote: > > > Paddy <[EMAIL PROTECTED]> writes: > > >> I've used Fortran and C and so would tend to use either i,j,k as the > >> unused loop variable above, or, for clarity, call it something

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

On 2008-05-12, Ben Finney <[EMAIL PROTECTED]> wrote: > Paddy <[EMAIL PROTECTED]> writes: > >> I've used Fortran and C and so would tend to use either i,j,k as the >> unused loop variable above, or, for clarity, call it something >> descriptive like loop_count, if the loop body would be clearer. > >

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

On 2008-05-12, Ben Finney <[EMAIL PROTECTED]> wrote: I too, agree that requiring a name be bound to the values coming out of the iterator seems "wrong". > With "do something N times", there must be *something* to keep track > of which iteration we're up to (or, equivalently, how many iterations >

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

On 2008-05-12, Ben Finney <[EMAIL PROTECTED]> wrote: >> Maybe my brain works differently, but I find both "dummy" and >> "unused" are extremely confusing names for loop counters. The loop >> begins to look like it doesn't iterate at all if its counter is >> dummy or unused. >> >> If it *counts* i

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

>> On Mon, 12 May 2008 16:24:23 +1000, Ben Finney wrote: [...] >> > That is also regrettably common in Python code. It still suffers from >> > being unnecessarily ambiguous, since there are *also* plenty of loops >> > using 'i', 'j', etc. where the loop counter *is* used. >> > >> > Differentiating

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

Paddy <[EMAIL PROTECTED]> writes: > I've used Fortran and C and so would tend to use either i,j,k as the > unused loop variable above, or, for clarity, call it something > descriptive like loop_count, if the loop body would be clearer. The problem with all of these names is that they also have lo

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

Ivan Illarionov <[EMAIL PROTECTED]> writes: > On Mon, 12 May 2008 16:24:23 +1000, Ben Finney wrote: > [...] > > That is also regrettably common in Python code. It still suffers > > from being unnecessarily ambiguous, since there are *also* plenty > > of loops using 'i', 'j', etc. where the loop co

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

John Salerno schreef: Ben Finney wrote: John Salerno <[EMAIL PROTECTED]> writes: num = 33 for x in xrange(10): print num += 1 Which is better done by 'num += 10'. Can you come up with an example that isn't trivially replaced with clearer code? That might make it clearer what your conce

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

On Mon, 12 May 2008 16:24:23 +1000, Ben Finney wrote: [...] > That is also regrettably common in Python code. It still suffers from > being unnecessarily ambiguous, since there are *also* plenty of loops > using 'i', 'j', etc. where the loop counter *is* used. > > Differentiating these use cases b

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

On May 11, 9:28 pm, Arnaud Delobelle <[EMAIL PROTECTED]> wrote: Hi John, Arnaud; > Contrived example: > > # Print 'hello' 10 times; x is not used > for x in xrange(10): > print 'hello' I've used Fortran and C and so would tend to use either i,j,k as the unused loop variable above, or, for cla

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

Ivan Illarionov <[EMAIL PROTECTED]> writes: > >> In such cases, the name 'dummy' is conventionally bound to the items > >> from the iterator, for clarity of purpose > [..] > > If a value isn't used, then I think the most clear name for it is > > "unused". > [...] > > Maybe my brain works differen

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

John Salerno <[EMAIL PROTECTED]> writes: > Ben Finney wrote: > > > John Salerno <[EMAIL PROTECTED]> writes: > > > >> num = 33 > >> > >> for x in xrange(10): > >> print num += 1 > > > > Which is better done by 'num += 10'. > > > > Can you come up with an example that isn't trivially replaced

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

>> In such cases, the name 'dummy' is conventionally bound to the items >> from the iterator, for clarity of purpose [..] > If a value isn't used, then I think the most clear name for it is > "unused". [...] Maybe my brain works differently, but I find both "dummy" and "unused" are extremely conf

Re: Convention for name indicating "don't care about the value" (was: Is using range() in for loops really Pythonic?)

On May 11, 11:41 pm, Ben Finney <[EMAIL PROTECTED]> wrote: > Carl Banks <[EMAIL PROTECTED]> writes: > > On May 11, 6:44 pm, Ben Finney <[EMAIL PROTECTED]> > > wrote: > > > In such cases, the name 'dummy' is conventionally bound to the items > > > from the iterator, for clarity of purpose:: > > > >

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

Ben Finney wrote: > John Salerno <[EMAIL PROTECTED]> writes: > >> num = 33 >> >> for x in xrange(10): >> print num += 1 > > Which is better done by 'num += 10'. > > Can you come up with an example that isn't trivially replaced with > clearer code? That might make it clearer what your concern

Convention for name indicating "don't care about the value" (was: Is using range() in for loops really Pythonic?)

Carl Banks <[EMAIL PROTECTED]> writes: > On May 11, 6:44 pm, Ben Finney <[EMAIL PROTECTED]> > wrote: > > In such cases, the name 'dummy' is conventionally bound to the items > > from the iterator, for clarity of purpose:: > > > > for dummy in range(10): > > # do stuff that makes no ref

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

On Sun, 11 May 2008 18:52:48 -0700, Carl Banks wrote: > On May 11, 6:44 pm, Ben Finney <[EMAIL PROTECTED]> > wrote: >> In such cases, the name 'dummy' is conventionally bound to the items >> from the iterator, for clarity of purpose:: >> >> for dummy in range(10): >> # do stuff that ma

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

On May 11, 6:44 pm, Ben Finney <[EMAIL PROTECTED]> wrote: > In such cases, the name 'dummy' is conventionally bound to the items > from the iterator, for clarity of purpose:: > > for dummy in range(10): > # do stuff that makes no reference to 'dummy' Is this documented? I've never hea

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

On Sun, 11 May 2008 16:16:53 -0400, John Salerno wrote (in message <[EMAIL PROTECTED]>): > XLiIV wrote: > >> The range() function returns a list and list is a sequence, isn't? > > I think you're missing the point. To me, there seems to be a fundamental > difference between these two things: >

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

John Salerno wrote: To me, the first example is a pure use of the for loop. You are iterating through an object and *using* the items you are stepping through. The second example, however, is simply doing something 10 times, and what it's doing has nothing to do with 'x' or xrange. So it see

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

John Salerno <[EMAIL PROTECTED]> writes: > num = 33 > > for x in xrange(10): > print num += 1 Which is better done by 'num += 10'. Can you come up with an example that isn't trivially replaced with clearer code? That might make it clearer what your concern is. > The [above] example [...] i

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

John Salerno <[EMAIL PROTECTED]> writes: > 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

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

XLiIV wrote: The range() function returns a list and list is a sequence, isn't? I think you're missing the point. To me, there seems to be a fundamental difference between these two things: --- people = ['Sam', 'Bob', 'Fred'] for name in people: print name --- AND --- num = 33 fo

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

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

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

"XLiIV" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] On May 11, 4:19 am, John Salerno <[EMAIL PROTECTED]> 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 ti

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

On May 11, 12:38 am, Paul Rubin wrote: > John Salerno <[EMAIL PROTECTED]> writes: > > 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 see

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

On May 11, 4:19 am, John Salerno <[EMAIL PROTECTED]> 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 o

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

John Salerno <[EMAIL PROTECTED]> writes: > 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 numb

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

On May 11, 3:19 am, John Salerno <[EMAIL PROTECTED]> 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 o

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

On May 10, 8:19 pm, John Salerno <[EMAIL PROTECTED]> 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 o

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

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.

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

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 itera

Is using range() in for loops really Pythonic?

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 so

Re: using range() in for loops

Georg Brandl <[EMAIL PROTECTED]> wrote: > Steven D'Aprano wrote: > > On Wed, 05 Apr 2006 16:15:12 +0200, Georg Brandl wrote: > > > >> [EMAIL PROTECTED] wrote: > >>> hi John, > >>> Python doesn't provide for loop like C / C++ but using Range() or > >>> Xrange() you can achive all the function

Re: using range() in for loops

Steven D'Aprano wrote: > On Wed, 05 Apr 2006 16:15:12 +0200, Georg Brandl wrote: > >> [EMAIL PROTECTED] wrote: >>> hi John, >>> Python doesn't provide for loop like C / C++ but using Range() or >>> Xrange() you can achive all the functionalities of the C for loop. >> >> Not quite. > > Care

Re: using range() in for loops

Steven D'Aprano wrote: > On Wed, 05 Apr 2006 16:21:02 +0200, Georg Brandl wrote: > >> Because of backwards compatibility. range() returns a list, xrange() an >> iterator: list(xrange(...)) will give the same results as range(...). > > Georg is pretty much correct in his explanation, but just to d

Re: using range() in for loops

On Wed, 05 Apr 2006 16:21:02 +0200, Georg Brandl wrote: > Because of backwards compatibility. range() returns a list, xrange() an > iterator: list(xrange(...)) will give the same results as range(...). Georg is pretty much correct in his explanation, but just to dot all the I's and cross all the

Re: using range() in for loops

On Wed, 05 Apr 2006 16:15:12 +0200, Georg Brandl wrote: > [EMAIL PROTECTED] wrote: >> hi John, >> Python doesn't provide for loop like C / C++ but using Range() or >> Xrange() you can achive all the functionalities of the C for loop. > > Not quite. Care to explain what the differences are,

Re: using range() in for loops

On Wed, 05 Apr 2006 09:16:37 -0400, AndyL wrote: > Paul Rubin wrote: >> Normally you'd use range or xrange. range builds a complete list in >> memory so can be expensive if the number is large. xrange just counts >> up to that number. > > so when range would be used instead of xrange. if xrange

Re: using range() in for loops

AndyL <[EMAIL PROTECTED]> wrote: >Paul Rubin wrote: >> Normally you'd use range or xrange. range builds a complete list in >> memory so can be expensive if the number is large. xrange just counts >> up to that number. >so when range would be used instead of xrange. if xrange is more >efficient,

Re: using range() in for loops

On Tue, 2006-04-04 at 21:54 -0400, John Salerno wrote: > I'm reading Text Processing in Python right now and I came across a > comment that is helping me to see for loops in a new light. I think > because I'm used to the C-style for loop where you create a counter > within the loop declaration,

Re: using range() in for loops

AndyL wrote: > Paul Rubin wrote: >> Normally you'd use range or xrange. range builds a complete list in >> memory so can be expensive if the number is large. xrange just counts >> up to that number. > > so when range would be used instead of xrange. if xrange is more > efficient, why range was

Re: using range() in for loops

[EMAIL PROTECTED] wrote: > hi John, > Python doesn't provide for loop like C / C++ but using Range() or > Xrange() you can achive all the functionalities of the C for loop. Not quite. Georg -- http://mail.python.org/mailman/listinfo/python-list

Re: using range() in for loops

Paul Rubin wrote: > Normally you'd use range or xrange. range builds a complete list in > memory so can be expensive if the number is large. xrange just counts > up to that number. so when range would be used instead of xrange. if xrange is more efficient, why range was not reimplemented? --

Re: using range() in for loops

Roel Schroeven wrote: > In many cases loops really are for iterating over sequences; more so > than I realized when using for loops in C or C++. In these cases, > Python's for statement works better than C-style loops. And if you > really need to do something a certain number of times, there's

Re: using range() in for loops

John Salerno schreef: > I'm reading Text Processing in Python right now and I came across a > comment that is helping me to see for loops in a new light. I think > because I'm used to the C-style for loop where you create a counter > within the loop declaration, for loops have always seemed to m

Re: using range() in for loops

It's not just a Python thing, Java for example generally uses the idiom: for (Iterator it = list.iterator(); it.hasNext(); ) { Object next = it.next(); //Do stuff to next } Horrible compared to the python idiom of course (though the latest version supports for (x : list){}) Ruby has some

Re: using range() in for loops

John Salerno wrote: > The reason for this distinction comes from the fact that I read a lot > how using range and for is somewhat discouraged, because it doesn't > really use a for loop for it's true purpose. So my question is, is this > just a Python-oriented opinion about for loops, or is it a ge

Re: using range() in for loops

hi John, Python doesn't provide for loop like C / C++ but using Range() or Xrange() you can achive all the functionalities of the C for loop.If you wants distributed for loop You can use Xrange. John Salerno wrote: > I'm reading Text Processing in Python right now and I came across a > comment

Re: using range() in for loops

John Salerno <[EMAIL PROTECTED]> writes: > The reason for this distinction comes from the fact that I read a lot > how using range and for is somewhat discouraged, because it doesn't > really use a for loop for it's true purpose. So my question is, is > this just a Python-oriented opinion about for

using range() in for loops

I'm reading Text Processing in Python right now and I came across a comment that is helping me to see for loops in a new light. I think because I'm used to the C-style for loop where you create a counter within the loop declaration, for loops have always seemed to me to be about doing something