Is there a way to delete an item from a dictionary in Python?
Additionally, how can I delete an item from a dictionary to return a copy (i.e., not modifying the original)?
del statement removes an element:
However, this mutates the existing dictionary so the contents of the dictionary changes for anybody else who has a reference to the same instance. To return a new dictionary, make a copy of the dictionary:
def removekey(d, key): r = dict(d) del r[key] return r
dict() constructor makes a shallow copy. To make a deep copy, see the
Note that making a copy for every dict
del/assignment/etc. means you're going from constant time to linear time, and also using linear space. For small dicts, this is not a problem. But if you're planning to make lots of copies of large dicts, you probably want a different data structure, like a HAMT (as described in this answer).