En Sun, 19 Apr 2009 15:41:02 -0300, Emmanuel Surleau
<emmanuel.surl...@gmail.com> escribió:
On Sunday 19 April 2009 19:37:59 Gabriel Genellina wrote:
En Sun, 19 Apr 2009 13:43:10 -0300, Emmanuel Surleau
> On an unrelated note, it would be *really* nice to have a length
> property on
> strings. Even Java has that!
Why would it be nice to have? I never missed it...
First off, it's pretty commonplace in OO languages. Secondly, given the
number of methods available for the string objects, it is only natural to
assume that dir("a") would show me a len() or length() or size() method.
Having to use a function for such a mundane operation feels unnatural and
not OO.
Perhaps in statically typed languages. Python is dynamic, so a x.length()
requires a method lookup and that's expensive. len(x) on the contrary, can
be optimized on a case by case basis -- it DOESN'T translate to
x.__len__() as some might think.
See
http://www.python.org/doc/faq/general/#why-does-python-use-methods-for-some-functionality-e-g-list-index-but-functions-for-other-e-g-len-list
On a side note, there is an alternative to dir(), more human-friendly:
http://inky.github.com/see/
py> see("a")
? [] in + * % < <= == != > >= len()
.capitalize()
.center() .count() .decode() .encode() .endswith()
.expandtabs()
.find() .format() .index() .isalnum() .isalpha() .isdigit()
.islower() .isspace() .istitle() .isupper() .join() .ljust()
.lower() .lstrip() .partition() .replace() .rfind() .rindex()
.rjust() .rpartition() .rsplit() .rstrip() .split()
.splitlines()
.startswith() .strip() .swapcase() .title() .translate()
.upper()
.zfill()
You can see len() there.
--
Gabriel Genellina
--
http://mail.python.org/mailman/listinfo/python-list
