Return copy of dictionary excluding specified keys

Question

I want to make a function that returns a copy of a dictionary excluding keys specified in a list.

Considering this dictionary:

my_dict = {     "keyA": 1,     "keyB": 2,     "keyC": 3 } 

A call to without_keys(my_dict, ['keyB', 'keyC']) should return:

{     "keyA": 1 } 

I would like to do this in a one-line with a neat dictionary comprehension but I'm having trouble. My attempt is this:

def without_keys(d, keys):     return {k: d[f] if k not in keys for f in d} 

which is invalid syntax. How can I do this?

Answer 1

You were close, try the snippet below:

>>> my_dict = { ...     "keyA": 1, ...     "keyB": 2, ...     "keyC": 3 ... } >>> invalid = {"keyA", "keyB"} >>> def without_keys(d, keys): ...     return {x: d[x] for x in d if x not in keys} >>> without_keys(my_dict, invalid) {'keyC': 3} 

Basically, the if k not in keys will go at the end of the dict comprehension in the above case.

Answer 2

In your dictionary comprehension you should be iterating over your dictionary (not k , not sure what that is either). Example -

return {k:v for k,v in d.items() if k not in keys}