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Set data structure..

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Alessio Pace

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Feb 19, 2003, 8:44:28 AM2/19/03

Hi, I am a python newbie, so this could be a silly question:
I need a Set like data structure, I just see list and dictionary as
built-in. Should I use one of those for my set purpose(I was thinking about
using a dictionary giving meaning only to the keys, but it seems a waste of
space for large inputs) and if so, which one has better access performance
to check if an element is in the set? Thanks!

Lexy Zhitenev

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Feb 19, 2003, 9:02:23 AM2/19/03

"Alessio Pace" <pucc...@yahoo.it> wrote:
news:uSL4a.20711$uA5.5...@tornado.fastwebnet.it...

I can't think of specialized Set classes, but I don't think that you're
gonna use very large sets. Then, the dictionaries is what you might wish.
The lookup of the keys is far faster than from lists.

Lexy.

Gerrit Holl

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Feb 19, 2003, 9:24:34 AM2/19/03

Alessio Pace schreef op woensdag 19 februari om 14:47:07 +0000:

As of Python 2.3, you can do:
18 >>> import sets
19 >>> myset = sets.Set(string.lowercase)
20 >>> myset
Set(['a', 'c', 'b', 'e', 'd', 'g', 'f', 'i', 'h', 'k', 'j', 'm', 'l', 'o', 'n', 'q', 'p', 's', 'r', 'u', 't', 'w', 'v', 'y', 'x', 'z'])

yours,
Gerrit.

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Alessio Pace

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Feb 19, 2003, 12:15:55 PM2/19/03

Gerrit Holl wrote:

> Alessio Pace schreef op woensdag 19 februari om 14:47:07 +0000:
>> Hi, I am a python newbie, so this could be a silly question:
>> I need a Set like data structure, I just see list and dictionary as
>> built-in. Should I use one of those for my set purpose(I was thinking
>> about using a dictionary giving meaning only to the keys, but it seems a
>> waste of space for large inputs) and if so, which one has better access
>> performance to check if an element is in the set? Thanks!
>
> As of Python 2.3, you can do:
> 18 >>> import sets
> 19 >>> myset = sets.Set(string.lowercase)
> 20 >>> myset
> Set(['a', 'c', 'b', 'e', 'd', 'g', 'f', 'i', 'h', 'k', 'j', 'm', 'l', 'o',
> 'n', 'q', 'p', 's', 'r', 'u', 't', 'w', 'v', 'y', 'x', 'z'])
>
> See also:
> http://www.python.org/doc/2.3a1/whatsnew/node2.html
> http://www.python.org/peps/pep-0218.html
> http://www.python.org/dev/doc/devel/lib/module-sets.html
>
> yours,
> Gerrit.
>

Thanks a lot! :-)

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