Python Dictionary setdefault() method

Python Dictionary setdefault() method

The dictionary.setdefault () method in Python returns the value of the item with the specified key.

Syntax

dictionary.setdefault(keyname, value)

Parameter

keyname- This parameter represents the keyname of the item you want to return the value.

value(optional)- This parameter represents a Key with a value default_value is inserted to the dictionary. If no value is provided, the default_value will be none. 

Return

This method returns an arbitrary element (key, value) pair from the given dictionary.

Example 1

 # Python program explaining
 # the dictionary.setdefault() method
 # initialising the dictionary
 fruits = {
  "banana" : "vitamins",
   "orange": "citric acid",
   "grapes": 5
 }
 # printing the Dictionary
 print("Dictionary:",fruits)
 # returning the value of the key.
 defaultValue=fruits.setdefault("grapes","vitamin c")
 print("Value of the key: \n", defaultValue) 

Output

Dictionary: {'grapes': 5, 'orange': 'citric acid', 'banana': 'vitamins'}
Value of the key: 5

Example 2

 # Python program explaining
 # the dictionary.setdefault() method
 # initializing the dictionary
 student = {'studentName': 'Reema','Roll No':'15cs1029'}
 # The given key is not in the dictionary
 branch = student.setdefault('branch')
 print('Student Details = ',student)
 print('Branch = ',branch)
 # The specified key is not in the dictionary
 # default_value is provided
 age = student.setdefault('age', 22)
 print('Student Details = ',student)
 print('age = ',age) 

Output

 Student Name =  {'Roll No': '15cs1029', 'branch': None, 'studentName': 'Reema'}
 Branch =  None
 Student Name =  {'Roll No': '15cs1029', 'age': 22, 'branch': None, 'studentName': 'Reema'}
 age =  22