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Dictionary Methods

fromkeys()

Create a new dictionary with keys from an iterable and a shared default value.

dict.fromkeys(iterable, value=None)

dict.fromkeys() is a class method that returns a new dictionary whose keys are taken from iterable and each mapped to value.

If value is omitted, all keys default to None.

Parameters

NameDescription
iterableAn iterable of keys (such as a list, tuple, or set).
valueOptional value assigned to each key. Defaults to None.

Returns

A new dictionary initialized with the specified keys.

Try it

Run it and change it
keys = ["cpu", "memory", "storage"]
status = dict.fromkeys(keys, "online")
print(status)

Worth knowing

  • Mutable value pitfall: If you provide a mutable object (like dict.fromkeys(keys, [])), all keys will reference the exact same list instance in memory. Use a dict comprehension {k: [] for k in keys} instead for mutable values.

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