splitting one dictionary into two

[wes weston]

Raymond Hettinger wrote:
> [jsaul]
> 
>>I have to split a dict into two dicts. Depending on their values,
>>the items shall remain in the original dict or be moved to another
>>one and at the same time be removed from the original dict.
>>
>>OK, this is how I do it right now:
>>
>>    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
>>
>>That means that I store the keys of the items to be removed from
>>the original dict in a list (klist) and subsequently remove the
>>items using these keys.
>>
>>Is there an "even more pythonic" way?
> 
> 
> Your way seems clean enough to me.
> 
> One other approach is to use items() so you can modify dict1 as you go:
> 
>     for key, value in dict1.items():
>         if value > 3:
>             dict2[key] = value
>             del dict1[key]
> 
> 
> 
> Raymond Hettinger

Raymond,
    I had the same approach seen above before the
originator added the fact that the starting
dictionaries would typically be "huge". Robert
Brewer timed this method as 5 times slower than
his method which showed me that my obsession with
simplicity needs to be looked at.
wes