The setdefault() method in Python dictionary is used to retrieve a value from a dictionary based on a specified key. If the key is present in the dictionary, it returns the corresponding value. If the key is not present, it inserts the key with a specified default value and returns this value. This method helps in avoiding KeyError when attempting to access a key that does not exist in the dictionary.
Parameter Values
| Parameter | Description |
|---|---|
| key | The key to be searched in the dictionary. |
| default | The value to be inserted in the dictionary if the key is not found. |
Return Values
The setdefault() method can return any type, as it returns the value of a dictionary key.
How to Use setdefault() in Python
Example 1:
The setdefault() method returns the value of a key in a dictionary. If the key does not exist, it inserts the key with the specified default value.
my_dict = {'a': 1, 'b': 2}
default_val = my_dict.setdefault('c', 3)
print(default_val) # Output: 3
print(my_dict) # Output: {'a': 1, 'b': 2, 'c': 3}