Em Ter, 2006-03-28 às 17:32 +0100, Sion Arrowsmith escreveu:
> ride. And at some point reversed() will become a win:
>
> $ python2.4 -mtimeit 'reversed(range(200))'
> 10 loops, best of 3: 6.65 usec per loop
> $ python2.4 -mtimeit 'range(200)[::-1]'
> 10 loops, best of 3: 6.88 usec per loop
Sathyaish wrote:
> How would you reverse a string "in place" in python? I am seeing that
> there are a lot of operations around higher level data structures and
> less emphasis on primitive data. I am a little lost and can't find my
> way through seeing a rev() or a reverse() or a strRev() functio
Sion Arrowsmith wrote:
> But note that a significant chunk is the join():
>
> $ python2.4 -mtimeit '"".join(reversed("foo"))'
> 10 loops, best of 3: 2.72 usec per loop
> $ python2.4 -mtimeit 'reversed("foo")'
> 100 loops, best of 3: 1.69 usec per loop
your second benchmark doesn't do any
Felipe Almeida Lessa <[EMAIL PROTECTED]> wrote:
>Em Ter, 2006-03-28 Ã s 16:03 +0100, Sion Arrowsmith escreveu:
>> >>> "".join(reversed("foo"))
>$ python2.4 -mtimeit '"".join(reversed("foo"))'
>10 loops, best of 3: 2.58 usec per loop
But note that a significant chunk is the join():
$ python2.
On Tue, 2006-03-28 at 06:15 -0800, Sathyaish wrote:
> And that the "extra-memory" operation I've given above is expensive, I
> believe. Is there an efficient way to do it?
>
How big is your string?
For short strings (i.e. where large means you don't have enough RAM to
hold one extra copy.)
>
Em Ter, 2006-03-28 às 16:03 +0100, Sion Arrowsmith escreveu:
> Rather than writing
> your own reversing code, you might like to look at:
>
> >>> "".join(reversed("foo"))
Or not:
$ python2.4
Python 2.4.2 (#2, Nov 20 2005, 17:04:48)
[GCC 4.0.3 2005 (prerelease) (Debian 4.0.2-4)] on linux2
Sathyaish wrote:
>> But what's got that to do with it? Strings are very mutable in C.
>
> I realized after posting that I'd said something incorrect again. The
> concept of "mutability" itself is a high-level concept compared to C.
> Memory allocation for strings is expensive because of the way ma
Sathyaish <[EMAIL PROTECTED]> wrote:
>How would you reverse a string "in place" in python?
> [ ... ]
>Forget it! I got the answer to my own question. Strings are immutable,
>*even* in python.
I'm not sure what that "*even*" is about, but glad that "You can't,
strings are immutable" is a satisfacto
>But what's got that to do with it? Strings are very mutable in C.
I realized after posting that I'd said something incorrect again. The
concept of "mutability" itself is a high-level concept compared to C.
Memory allocation for strings is expensive because of the way malloc()
works to find a "bes
Sathyaish wrote:
> And that the "extra-memory" operation I've given above is expensive, I
> believe. Is there an efficient way to do it?
>
If i recall correctly a string is an immutable list.
I would do it this way:
>>> strTXT = "foo"
>>> strREV = strTXT[::-1]
>>> strREV
'oof'
--
mph
--
http
On 28 Mar 2006 06:08:51 -0800, Sathyaish <[EMAIL PROTECTED]> wrote:
>How would you reverse a string "in place" in python? I am seeing that
>there are a lot of operations around higher level data structures and
>less emphasis on primitive data. I am a little lost and can't find my
>way through seein
Sathyaish enlightened us with:
> How would you reverse a string "in place" in python?
You wouldn't, since strings are immutable.
> Forget it! I got the answer to my own question. Strings are
> immutable, *even* in python.
Indeed :)
> Why not! The python compiler is written in C, right?
Yup. Bu
And that the "extra-memory" operation I've given above is expensive, I
believe. Is there an efficient way to do it?
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How would you reverse a string "in place" in python? I am seeing that
there are a lot of operations around higher level data structures and
less emphasis on primitive data. I am a little lost and can't find my
way through seeing a rev() or a reverse() or a strRev() function around
a string object.
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