while true: !!!

Bjorn Pettersen pbjorn at uswest.net
Tue Dec 19 15:39:50 CET 2000


Steve Lamb wrote:

> On Mon, 18 Dec 2000 07:38:52 -0700, Bjorn Pettersen <pbjorn at uswest.net> wrote:
> [snip[
> >   for line in f.readlines():
> >      ...
>     Which...
> >has the potential of crashing your machine with an out-of-memory error if you
> >don't know the sizes of files you're operating on.
>     ...wastes memory.

Well, if you have it, and use it, you're hardly wasting it <wink>.

> >So, the status quo is that because the straight-forward way of doing it is
> >too slow, we're all using an optimized idiom that while easy to understand if
> >coming from a CS background, doesn't model what you're doing (at least not
> >until you've programmed enough Python that reading a file seems like an
> >endless loop <wink>).
>
>     Or doing it in the 2-3 other languages I know of which use while in the
> exact same manner.  I'm sure if we took a pole of the computer languages known
> here you'd find that it is pretty much a standard across many languages, not
> just Python.

Thank you for restating what I said: coming from a CS background/other languages,
"while 1:" is quite understandable. I don't think this is necessarily an area
worth mimicking other languages though (especially since one of the main arguments
for adding += to the language was because it closer modelled the intended semantic
of the expression).

>     Hell, if you want to grouse about readability in Python, why not attack
> some of the more obvious targets?
> [snip examples of else clauses on for and while loops]

So you're arguing that since Python is so unreadable in it's use of else clauses,
"while 1:" hardly matters? <wink>

-- bjorn

ps: the only questions I have seen about "else on while" have indicated that
beginners expect the else clause to be executed if the condition fails the first
time (I could probably come up with a coherent argument for why that is the
"negative" of a loop <wink>)
pps: I did enjoy the "while 1: ... else: ..." construct ;-)





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