Removing key values pairs from a list of dictionaries

def new_dict(old_dict):
    n = old_dict.copy()
    n.pop('mykey1',None)
    return n

new_list_of_dict = map(new_dict,list_of_dict)

or

new_list_of_dict = [ new_dict(d) for d in list_of_dict ]

Rather than using del, I opted for dict.pop since pop will suppress the KeyError if the key doesn't exist.

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If you really only want to get certain keys, this becomes a bit easier.

from operator import itemgetter
tuple_keys = ('key1','key2','key3')
get_keys = itemgetter(*tuple_keys)
new_dict_list = [ dict(zip(tuple_keys,get_keys(d)) for d in old_dict_list ] 

which raises KeyError if the keys aren't in the old dict

Or:

new_dict_list = [ dict( (k,d.get(k,None)) for k in tuple_keys ) for d in old_dict_list ]

which will also add key:None if key isn't in the old dict. If you don't want that None, you could do:

new_dict_list = [ dict( (k,d[k]) for k in tuple_keys if k in d) for d in old_dict_list ]

Depending on what percent of the dictionary you're including/excluding and the size of the dictionaries, this might be slightly faster than the solution by @MartijnPieters.

If you really want to use a list comprehension, combine it with a dict comprehension:

[{k: v for k, v in d.iteritems() if k != 'mykey1'} for d in mylist]

Substitute .iteritems() for .items() if you are on python 3.

On python 2.6 and below you should use:

[dict((k, v) for k, v in d.iteritems() if k != 'mykey1') for d in mylist]

as the {key: value ...} dict comprehension syntax was only introduced in Python 2.7 and 3.

[d.pop('mykey1', None) for d in list]