The setdefault() function in python helps to return the value of the key which is in the dictionary. If the key is not in the dictionary, then a new key is inserted with the specified value to the dictionary.
dict.setdefault(key[, default_value]) #where the key is to be searched
The setdefault() function takes two parameters.If the parameter 'default_value' is not given it will be taken as none.
| Parameter | Description | Required / Optional |
|---|---|---|
| key | the key to be searched in the dictionary | Required |
| default_value | key with a value default_value is inserted into the dictionary if the key is not in the dictionary | optional |
The method’s return value depends on the input parameters given.
| Input | Return Value |
|---|---|
| if it in a dictionary | key-value |
| if key not in dictionary & no defalt_value | None |
| if key not in dictionary & defalt_value is given | default_value |
persondet = {'name': 'Jhon', 'age': 35}
age = persondet.setdefault('age')
print('personal details = ',persondet)
print('Age = ',age)
Output:
personal details = {'name': 'Jhon', 'age': 35}
Age = 35
persondet = {'name': 'Jhon'}
# key is not in the dictionary
salary = persondet.setdefault('salary')
print('personal details = ',persondet)
print('salary = ',salary)
# key is not in the dictionary
# default_value is provided
age = persondet.setdefault('age', 35)
print('personal details = ',persondet)
print('age = ',age)
Output:
personal details = {'name': 'Jhon', 'salary': None}
salary = None
personal details = {'name': 'Jhon', 'age': 35, 'salary': None}
age = 35
