How to remove a key from a python dictionary?

When trying to delete a key from a dictionary, I write:

if 'key' in myDict:
    del myDict['key']

Is there a one line way of doing this?

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Use dict.pop() :

my_dict.pop('key', None)

This will return my_dict[key] if key exists in the dictionary, and None otherwise. If the second parameter is not specified (ie. my_dict.pop('key') ) and key does not exist, a KeyError is raised.

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Specifically to answer "is there a one line way of doing this?"

if 'key' in myDict: del myDict['key']

...well, you asked ;-)

You should consider, though, that this way of deleting an object from a dict is not atomic—it is possible that 'key' may be in myDict during the if statement, but may be deleted before del is executed, in which case del will fail with a KeyError . Given this, it would be safest to either use dict.pop or something along the lines of

try:
    del myDict['key']
except KeyError:
    pass

which, of course, is definitely not a one-liner.

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It took me some time to figure out what exactly my_dict.pop("key", None) is doing. So I'll add this as an answer to save others googling time:

pop(key[, default])

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

Documentation

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