loops

[Steven D'Aprano]

Re: loops

On Sat, 18 Oct 2008 20:45:47 -0700, John Machin wrote:

On Oct 19, 2:30 pm, Steven D'Aprano <st...@REMOVE-THIS-
cybersource.com .auwrote:
[snip]

>making your code easy to read and easy to maintain is far more
>important.
>>
>for x in (2**i for i in xrange(10)):
>    print x
>>
>will also print 1, 2, 4, 8, ... up to 1000.

>
I would say up to 512; perhaps your understanding of "up to" differs
from mine.

Well, mine is based on Python's half-open semantics: "up to" 1000 doesn't
include 1000, and the highest power of 2 less than 1000 is 512.

Perhaps you meant "up to and including 512".

Easy to read? I'd suggest this:
>
for i in xrange(10):
print 2 ** i

Well, sure, if you want to do it the right way *wink*.

But seriously, no, that doesn't answer the OP's question. Look at his
original code (which I assume is C-like pseudo-code):

for x=1;x<=100;x+x:
print x

The loop variable i takes the values 1, 2, 4, 8, etc. That's what my code
does. If he was asking how to write the following in Python, your answer
would be appropriate:

for x=1;x<=100;x++:
print 2**x



--
Steven

[John Machin]

Re: loops



Steven D'Aprano wrote:

On Sat, 18 Oct 2008 20:45:47 -0700, John Machin wrote:
>

On Oct 19, 2:30 pm, Steven D'Aprano <st...@REMOVE-THIS-
cybersource.com .auwrote:
[snip]

making your code easy to read and easy to maintain is far more
important.
>
for x in (2**i for i in xrange(10)):
    print x
>
will also print 1, 2, 4, 8, ... up to 1000.

I would say up to 512; perhaps your understanding of "up to" differs
from mine.

>
Well, mine is based on Python's half-open semantics: "up to" 1000 doesn't
include 1000, and the highest power of 2 less than 1000 is 512.

We're talking about an English sentence, not a piece of Python code.
When you say "I'm taking the train to X", do you get off at the
station before X, as in "getting off at Redfern"?

>
Perhaps you meant "up to and including 512".
>

[Steven D'Aprano]

Re: loops

On Sun, 19 Oct 2008 03:17:51 -0700, John Machin wrote:

Steven D'Aprano wrote:
>

>On Sat, 18 Oct 2008 20:45:47 -0700, John Machin wrote:
>>

On Oct 19, 2:30 pm, Steven D'Aprano <st...@REMOVE-THIS-
cybersource.com .auwrote:
[snip]
>making your code easy to read and easy to maintain is far more
>important.
>>
>for x in (2**i for i in xrange(10)):
>    print x
>>
>will also print 1, 2, 4, 8, ... up to 1000.
>
I would say up to 512; perhaps your understanding of "up to" differs
from mine.

>>
>Well, mine is based on Python's half-open semantics: "up to" 1000
>doesn't include 1000, and the highest power of 2 less than 1000 is 512.

>
We're talking about an English sentence, not a piece of Python code.
When you say "I'm taking the train to X", do you get off at the station
before X, as in "getting off at Redfern"?

But I don't say "I'm taking the train UP TO X".

Intervals in English are often ambiguous, which is why people often
explicitly say "up to and including...". But in this specific case, I
don't see why you're having difficulty. Whether 1000 was included or not
makes no difference, because 1000 is not a power of 2.


--
Steven