Python Dictionary Methods
Python Dictionary Methods
Python has a set of built-in methods that dictionary objects can call. All the python dictionary methods are as follow:
| Methods | Description |
| clear() | The dictionary.clear() method removes all the elements from the dictionary. |
| copy() | The dictionary.copy() method returns a copy of the specified Dictionary. |
| fromkeys() | The dictionary.fromkeys() method returns a dictionary with the specified keys and values. |
| get() | This method returns the value for the given key. |
| items() | The dictionary.items() method returns a list containing a tuple for each key value pair |
| keys() | This method returns View Object of All Keys |
| pop() | The dictionary.pop() method removes and returns element having the specified key. |
| popitem() | This method removes the last inserted key-value pair |
| setdefault() | The dictionary.setdefault() method inserts Key with a Value if Key is not Present and returns the value of the specified key |
| update() | The dictionary.update()updates the dictionary with the specified key-value pairs |
| values() | This method returns a list of all the values in the dictionary |
Example 1
# Python program explaining
# the dictionary methods
# initialising the dictionary
fruits = {
"banana" : "apple",
"orange": "mango",
"grapes": 5
}
# printing the Dictionary
print("Dictionary:",fruits)
# the setdefault() method
# returning the value of the key.
print("The setdefault() method..")
defaultValue=fruits.setdefault("grapes","vitamin c")
print("\nValue of the key: \n", defaultValue)
# the popitem() method
# pop the last element
fruits.popitem()
print("\nAfter poping the last item..")
print('Remaining dictionary: ', fruits)
# the pop() method
# removing the "banana" element from the dictionary.
leftFruit=fruits.pop("banana")
print("\nMy final lists of fruits are\n", fruits)
Output
Dictionary: {'orange': 'mango', 'banana': 'apple', 'grapes': 5}
The setdefault() method..
Value of the key:
5
After poping the last item..
Remaining dictionary: {'banana': 'apple', 'grapes': 5}
My final lists of fruits are
{'grapes': 5}
Example 2
# Python program explaining
# the dictionary methods
# initializing the student dictionary
student = {'studentName': 'Reema','Roll No':'15cs1029'}
print("The actual Student Details:",student)
# initializing the second dicitonary with updated values
updatedStudent= {'studentName': 'Reema','Roll No':'15ME1028','age':22}
# the dictionary.update() method
# update the value of key 'Roll'
student.update(updatedStudent)
print("Student details after updation:")
print(student)
# the dictionary.get() method
# will return the key value of name and language
print('Student Name: ', student.get('studentName'))
print('Roll No: ', student.get('Roll No'))
# the dictionary.items() method
# returns a view object that displays a list of a given dictionary's tuple pair
items = student.items()
print('Original week list:', items)
Output
The actual Student Details: {'studentName': 'Reema', 'Roll No': '15cs1029'}
Student details after updation:
{'age': 22, 'studentName': 'Reema', 'Roll No': '15ME1028'}
Student Name: Reema
Roll No: 15ME1028
Original week list: dict_items([('age', 22), ('studentName', 'Reema'), ('Roll No', '15ME1028')])
Example 3
# Python program explaining
# the dictionary methods
# initializing the week dictionary
week = { 'Monday': 1, 'Tuesday': 2, 'wednesday': 3 ,'Thursday':4,'Friday':5}
print("Actual dictionary:",week)
# the dictionary.keys() method
# Returning a list containing the dictionary's keys
items = week.keys()
print('Original week list:', items)
# the dictionary.copy() method
# copying the elements of dictionary in dictionary1
dictionary1 = week.copy()
print("After copying the dictionary elements in dictionary1...")
print('dictionary1: ', dictionary1)
# the dictionary.clear() method
# clearing all the elements
week.clear()
print('Removing all the element using clear()')
print('Week List : ', week)
print('dictionary1: ', dictionary1)
Output
Actual dictionary: {'wednesday': 3, 'Friday': 5, 'Tuesday': 2, 'Thursday': 4, 'Monday': 1}
Original week list: dict_keys(['wednesday', 'Friday', 'Tuesday', 'Thursday', 'Monday'])
After copying the dictionary elements in dictionary1...
dictionary1: {'wednesday': 3, 'Friday': 5, 'Tuesday': 2, 'Thursday': 4, 'Monday': 1}
Removing all the element using clear()
Week List : {}
dictionary1: {'wednesday': 3, 'Friday': 5, 'Tuesday': 2, 'Thursday': 4, 'Monday': 1}