list to dict
Bart Nessux
bart_nessux at hotmail.com
Wed Jun 16 13:11:03 EDT 2004
Josef Dalcolmo wrote:
> on Wed, 16 Jun 2004 09:29:23 -0400
> Bart Nessux <bart_nessux at hotmail.com> wrote:
>
>
>>What is the easiest/fastest way to build a dictionary from a list? The
>>list contains 100,000 entries.
>
>
> The first question would be, what should the keys be? If the list consists of unique, unmutable items, then you might use the items themselves as key and write:
>
> mydict = dict(zip(mylist, mylist))
>
> obtaining a dictionary with all the keys and values identical (therefore somewhat of a waste, but occasionally useful). Note: if your original list did not contain unique values, you end up with a set.
>
> If you want to remember the original order of the list, then write
>
> mydict = dict(zip(mylist, xrange(len(mylist))))
>
>
> If you don't care about the key (that would be strange) then you can write:
>
> mydict = dict(zip(xrange(len(mylist)), mylist))
>
> Instead of len(mylist) you can also write 1000000 or any other number larger than your list.
>
>
> - Josef
Josef,
This was great. I understand how this works now. Thanks for such a
broad, yet applicable explanation!
Bart
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