splitting one dictionary into two

[jsaul]

* Peter Otten [2004-04-01 18:46]:
> jsaul wrote:
>
> >     dict1 = { "a":1, "b":3, "c":5, "d":4, "e":2 }
> >     dict2 = {}
> >     klist = []
> >
> >     for key in dict1:
> >         if dict1[key] > 3: # some criterion
> >             dict2[key] = dict1[key]
> >             klist.append(key)
> >
> >     for key in klist:
> >         del dict1[key]
> >
> >     print dict1
> >     print dict2
>
> Only a minor change to do away with the temporary list:
>
>     for key in dict1:
>         if dict1[key] > 3: # some criterion
>             dict2[key] = dict1[key]
>
>     for key in dict2:
>         del dict1[key]

Hi Peter and others who responded so quickly,

I notice now that I forgot to mention an important condition,
namely that in real life dict2 is already existing and may have
become huge. That's the reason why I need to somewhere save only
those items which I most recently removed from the 1st dict, as
I want to avoid iterating over the while dict2. In real life,
dict1 contains pending jobs which, after they are done, are moved
to a second dict for post processing.

Sorry for the confusion.

I think the most "pythonic" candidate is actually the version
suggested by Larry, namely

    dict1 = { "a":1, "b":3, "c":5, "d":4, "e":2 }
    dict2 = {} # in real life, dict2 already exists

    for key in dict1.keys():
        if dict1[key] > 3:
            dict2[key] = dict1.pop(key)

    print dict1
    print dict2

Cheers, jsaul