Python dictionary Method - setdefault()-IGI

https:/‮gi.www/‬iftidea.com

The setdefault() method is a dictionary method in Python that returns the value for a given key in a dictionary. If the key is not present in the dictionary, it sets the key to a default value and returns that value.

The syntax for using setdefault() is as follows:

dict.setdefault(key, default_value)

The method takes two arguments: key and default_value. If the key is present in the dictionary, setdefault() returns its value. If the key is not present, it adds the key to the dictionary with the default_value as its value and returns default_value.

Here is an example that demonstrates the use of setdefault():

>>> d = {'a': 1, 'b': 2}
>>> x = d.setdefault('c', 3)
>>> print(x)
3
>>> print(d)
{'a': 1, 'b': 2, 'c': 3}
>>> y = d.setdefault('a', 4)
>>> print(y)
1
>>> print(d)
{'a': 1, 'b': 2, 'c': 3}

In this example, setdefault() is used to get the value for the key 'c' in the dictionary d. Since the key 'c' is not present in the dictionary, setdefault() adds it to the dictionary with the value 3 and returns 3.

Next, setdefault() is used to get the value for the key 'a'. Since the key 'a' is present in the dictionary, setdefault() returns its value (1) and does not modify the dictionary.

In summary, setdefault() provides a way to get the value of a key in a dictionary and to set a default value if the key is not present in the dictionary. It can be useful in cases where you want to set default values for keys that may not be present in a dictionary.

tutorial

Python dictionary Method - setdefault()