The syntax of keys() is:
dict.keys()
keys() Parameters
keys() doesn't take any parameters.
Return Value from keys()
keys() returns a view object that displays a list of all the keys.
When the dictionary is changed, the view object also reflects these changes.
Example 1: How keys() works?
person = {'name': 'Phill', 'age': 22, 'salary': 3500.0}
print(person.keys())
empty_dict = {}
print(empty_dict.keys())
Output
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)
Output
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.