How to delete entries in a dictionary with a given flag in python?

Question

Hey!

I have a dictionary, lets call it myDict, in Python that contains a set of similar dictionaries which all have the entry "turned_on : True" or "turned_on : False". I want to remove all the entries in myDict that are off, e.g. where "turned_on : False". In Ruby I would do something like this:

myDict.delete_if { |id,dict| not dict[:turned_on] }

How should I do this in Python?

Answer 1

Straight-forward way:

def delete_if_not(predicate_key, some_dict):
    for key, subdict in some_dict.items():
        if not subdict.get(predicate_key, True):
            del some_dict[key]

Testing:

mydict = {
        'test1': {
                'turned_on': True,
                'other_data': 'foo',
            },
        'test2': {
            'turned_on': False,
            'other_data': 'bar',
            },
        }
delete_if_not('turned_on', mydict)
print mydict

The other answers on this page so far create another dict. They don't delete the keys in your actual dict.

Answer 2

It's not clear what you want, but my guess is:

myDict = {i: j for i, j in myDict.items() if j['turned_on']}

or for older version of python:

myDict = dict((i, j) for i, j in myDict.iteritems() if j['turned_on'])

Answer 3

You mean like this?

myDict = {"id1" : {"turned_on": True}, "id2" : {"turned_on": False}}
result = dict((a, b) for a, b in myDict.items() if b["turned_on"])

output:

{'id1': {'turned_on': True}}

Answer 4

d = { 'id1':{'turned_on':True}, 'id2':{'turned_on':False}}
dict((i,j) for i, j in d.items() if not j['turned_on'])