Equivalent of std::set

[Nicolas Fleury]

Hi,

I haven't work so much in python and I was wondering what python
programmers use for string collections, like an equivalent of C++
std::set. Do you use a dictionary with dummy values? Tuple/list? Is
there any other structure in some module with uniqueness ensured and
lookup optimised? I'm only interested in storing strings in that structure.

Thx for help

Nicolas

[anton muhin]

Re: Equivalent of std::set

Nicolas Fleury wrote:[color=blue]
> Hi,
>
> I haven't work so much in python and I was wondering what python
> programmers use for string collections, like an equivalent of C++
> std::set. Do you use a dictionary with dummy values? Tuple/list? Is
> there any other structure in some module with uniqueness ensured and
> lookup optimised? I'm only interested in storing strings in that
> structure.
>
> Thx for help
>
> Nicolas
>[/color]

Python 2.3 introduced Set type, in the former versions common idiom was
to use dictionaries with dummies IMHO.

anton.

[Stephen Horne]

Re: Equivalent of std::set

On Fri, 26 Sep 2003 10:07:20 -0400, Nicolas Fleury
<nid_oizo@yahoo .com_remove_the _> wrote:
[color=blue]
>Hi,
>
>I haven't work so much in python and I was wondering what python
>programmers use for string collections, like an equivalent of C++
>std::set. Do you use a dictionary with dummy values? Tuple/list? Is
>there any other structure in some module with uniqueness ensured and
>lookup optimised? I'm only interested in storing strings in that structure.
>
>Thx for help
>
>Nicolas[/color]

A set type was introduced in Python 2.3...

http://www.python.org/doc/2.3/whatsnew/whatsnew23.html

http://www.python.org/doc/2.3/lib/module-sets.html

There are other ways, depending on what you are doing with the
strings, though.

For instance, although you can iterate a set, the iteration will not
necessarily be in order (I assume it uses hashing internally, probably
by using a dictionary internally). If you need to access the strings
in order (and there aren't too many of them) you can keep the items in
a sorted list, in which case the bisect module will probably be a big
help.


--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk