Python Dictionary keys()

The syntax of keys() is:

dict.keys()

keys() Parameters

The keys() doesn't take any parameters.

Return Value from keys()

The keys() returns a view object that displays a list of all the keys.

When the dictionary is changed, the view object also reflect these changes.

Example 1: How keys() works?

person = {'name': 'Phill', 'age': 22, 'salary': 3500.0}
print(person.keys())

empty_dict = {}
print(empty_dict.keys())

When you run the program, the output will be:

dict_keys(['name', 'salary', 'age'])
dict_keys([])

Example 2: How keys() works when dictionary is updated?

person = {'name': 'Phill', 'age': 22, }

print('Before dictionary is updated')
keys = person.keys()
print(keys)

# adding an element to the dictionary
person.update({'salary': 3500.0})
print('\nAfter dictionary is updated')
print(keys)

When you run the program, the output will be:

Before dictionary is updated
dict_keys(['name', 'age'])

After dictionary is updated
dict_keys(['name', 'age', 'salary'])

Here, when the dictionary is updated, keys is also automatically updated to reflect changes.