Remove keys that may not exist from dict in Python

Question: Question:

I use del to remove a key from a dict in Python, but I get a KeyError if the key I'm trying to remove doesn't exist.

>>> a = dict(a=1, b=2)
>>> del a["c"]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 'c'

In order to avoid this, it is necessary to check in advance whether the key exists as shown below.

>>> a = dict(a=1, b=2)
>>> if "c" in a:
...     del a["c"]

Is there an easier way to write to remove a key that may not exist?

Answer: Answer:

Use dict.pop

a = dict(a=1, b=2)
a.pop('c', None) # None
print a          # {'a': 1, 'b': 2}
a.pop('a', None) # 1
print a          # {'b': 2}

If key is in the dictionary, remove it and return its value, else return default . If default is not given and key is not in the dictionary, a KeyError is raised.

pop(key[, default]) removes the key from the dictionary and returns the value of the element, or default . If you don't pass the second argument default when popping an pop key, you'll get a KeyError . You can specify it with None as in the above example.

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