Overview Comments User Input Numbers Booleans History Hello World Program Environment Setup Syntax Variables Data Types Type Casting Unicode System Literals Operators

Control Flow Break Statement Continue Statement Pass Statement Nested Loops Decision Making If Statement If-else Statement Nested IF Statement Match-Case Statement Loops For Loops For-else Loops While Loops

Functions Built-in Functions Default Arguments Keyword Arguments Keyword-Only Arguments Positional Arguments Positional-Only Arguments Arbitrary Arguments Variable Scope Function Annotations Modules

String Slicing Strings Modify Strings String Concatenation String Formatting Escape Characters String Methods String Exercises

Lists List Exercises Access List Items Change List Items Add List Items Remove List Items Loop Lists List Comprehension Sort Lists Copy Lists Join Lists List Methods

Tuples Access Tuple Items Update Tuples Unpack Tuple Items Loop Tuples Join Tuples Tuple Methods Tuple Exercises

Sets Access Set Items Add Set Items Remove Set Items Loop Sets Join Sets Copy Sets Set Operators Set Methods Set Exercises

Dictionaries Dictionary Exercises Access Dictionary Items Change Dictionary Items Add Dictionary Items Remove Dictionary Items Dictionary View Objects Loop Dictionaries Copy Dictionaries Nested Dictionaries Dictionary Methods

Arrays Access Array Items Add Array Items Remove Array Items Loop Arrays Copy Arrays Reverse Arrays Sort Arrays Join Arrays Array Methods Array Exercises

File Handling Write to File Read Files Renaming and Deleting Files Directories File Methods

Feedback

Submit request if you have any questions.

Course

Add Dictionary Items

Python Tutorial

This Python tutorial has been written for the beginners to help them understand the basic to advanced concepts of Python Programming Language. After completing this tutorial, you will find yourself at a great level of expertise in Python, from where you can take yourself to the next levels to become a world class Software Engineer.

Add Dictionary Items
Using the Operator
The "[]" operator (used to access value mapped to a dictionary key) is used to update an existing key-value pair as well as add a new pair.
Syntax
dict["key"] = val
If the key is already present in the dictionary object, its value will be updated to val. If the key is not present in the dictionary, a new key-value pair will be added.
Example
In this example, the marks of "Laxman" are updated to 95.
marks = {"Savita":67, "Imtiaz":88, "Laxman":91, "David":49}
print ("marks dictionary before update: ", marks)
marks['Laxman'] = 95
print ("marks dictionary after update: ", marks)
It will produce the following output
marks dictionary before update: {'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49}
marks dictionary after update: {'Savita': 67, 'Imtiaz': 88, 'Laxman': 95, 'David': 49}
Example
However, an item with 'Krishnan' as its key is not available in the dictionary, hence a new key-value pair is added.
marks = {"Savita":67, "Imtiaz":88, "Laxman":91, "David":49}
print ("marks dictionary before update: ", marks)
marks['Krishan'] = 74
print ("marks dictionary after update: ", marks)
It will produce the following output
marks dictionary before update: {'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49}
marks dictionary after update: {'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49, 'Krishan': 74}
Using the update() Method
You can use the update() method in dict class in three different ways:
Update with Another Dictionary
In this case, the update() method's argument is another dictionary. Value of keys common in both dictionaries is updated. For new keys, key-value pair is added in the existing dictionary
Syntax
d1.update(d2)
Return value
The existing dictionary is updated with new key-value pairs added to it.
Example
marks = {"Savita":67, "Imtiaz":88, "Laxman":91, "David":49}
print ("marks dictionary before update: \n", marks)
marks1 = {"Sharad": 51, "Mushtaq": 61, "Laxman": 89}
marks.update(marks1)
print ("marks dictionary after update: \n", marks)
It will produce the following output
marks dictionary before update:
{'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49}
marks dictionary after update:
{'Savita': 67, 'Imtiaz': 88, 'Laxman': 89, 'David': 49, 'Sharad': 51, 'Mushtaq': 61}
Update with Iterable
If the argument to update() method is a list or tuple of two item tuples, an item each for it is added in the existing dictionary, or updated if the key is existing.
Syntax
d1.update([(k1, v1), (k2, v2)])
Return value
Existing dictionary is updated with new keys added.
Example
marks = {"Savita":67, "Imtiaz":88, "Laxman":91, "David":49}
print ("marks dictionary before update: \n", marks)
marks1 = [("Sharad", 51), ("Mushtaq", 61), ("Laxman", 89)]
marks.update(marks1)
print ("marks dictionary after update: \n", marks)
It will produce the following output
marks dictionary before update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49}
marks dictionary after update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 89, 'David': 49, 'Sharad': 51, 'Mushtaq': 61}
Practice with Online Editor
Note: This Python online Editor is a Python interpreter written in Rust, RustPython may not fully support all Python standard libraries and third-party libraries yet.
Remember to save code(Ctrl + S Or Command + S) before run it.
﻿
Update with Keyword Arguments
Third version of update() method accepts list of keyword arguments in name=value format. New k-v pairs are added, or value of existing key is updated.
Syntax
d1.update(k1=v1, k2=v2)
Return value
Existing dictionary is updated with new key-value pairs added.
Example
marks = {"Savita":67, "Imtiaz":88, "Laxman":91, "David":49}
print ("marks dictionary before update: \n", marks)
marks.update(Sharad = 51, Mushtaq = 61, Laxman = 89)
print ("marks dictionary after update: \n", marks)
It will produce the following output
marks dictionary before update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49}
marks dictionary after update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 89, 'David': 49, 'Sharad': 51, 'Mushtaq': 61}
Using the Unpack Operator
The "**" symbol prefixed to a dictionary object unpacks it to a list of tuples, each tuple with key and value. Two dict objects are unpacked and merged together and obtain a new dictionary.
Syntax
d3 = {**d1, **d2}
Return value
Two dictionaries are merged and a new object is returned.
Example
marks = {"Savita":67, "Imtiaz":88, "Laxman":91, "David":49}
print ("marks dictionary before update: \n", marks)
marks1 = {"Sharad": 51, "Mushtaq": 61, "Laxman": 89}
newmarks = {**marks, **marks1}
print ("marks dictionary after update: \n", newmarks)
It will produce the following output
marks dictionary before update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49}
marks dictionary after update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 89, 'David': 49, 'Sharad': 51, 'Mushtaq': 61}
Using the Union Operator (|)
Python introduces the "|" (pipe symbol) as the union operator for dictionary operands. It updates existing keys in dict object on left, and adds new key-value pairs to return a new dict object.
Syntax
d3 = d1 | d2
Return value
The Union operator return a new dict object after merging the two dict operands
Example
marks = {"Savita":67, "Imtiaz":88, "Laxman":91, "David":49}
print ("marks dictionary before update: \n", marks)
marks1 = {"Sharad": 51, "Mushtaq": 61, "Laxman": 89}
newmarks = marks | marks1
print ("marks dictionary after update: \n", newmarks)
It will produce the following output
marks dictionary before update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49}
marks dictionary after update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 89, 'David': 49, 'Sharad': 51, 'Mushtaq': 61}
Using "|=" Operator
The "|=" operator is an augmented Union operator. It performs in-place update o n the dictionary operand on left by adding new keys in the operand on right, and updating the existing keys.
Syntax
d1 |= d2
Example
marks = {"Savita":67, "Imtiaz":88, "Laxman":91, "David":49}
print ("marks dictionary before update: \n", marks)
marks1 = {"Sharad": 51, "Mushtaq": 61, "Laxman": 89}
marks |= marks1
print ("marks dictionary after update: \n", marks)
It will produce the following output
marks dictionary before update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 91, 'David': 49}
marks dictionary after update:
 {'Savita': 67, 'Imtiaz': 88, 'Laxman': 89, 'David': 49, 'Sharad': 51, 'Mushtaq': 61}
Practice with Online Editor
Note: This Python online Editor is a Python interpreter written in Rust, RustPython may not fully support all Python standard libraries and third-party libraries yet.
Remember to save code(Ctrl + S Or Command + S) before run it.
﻿
﻿
﻿


﻿

Python Basics

Python Control Statement

Python Functions & Modules

Python Strings

Python Lists

Python Tuples

Python Sets

Python Dictionaries

Python Arrays

Python File Handling

Object Oriented Programming

Python Tutorial

Add Dictionary Items

Using the Operator

Syntax

Example

Example

Using the update() Method

Update with Another Dictionary

Syntax

Return value

Example

Update with Iterable

Syntax

Return value

Example

Practice with Online Editor

Update with Keyword Arguments

Syntax

Return value

Example

Using the Unpack Operator

Syntax

Return value

Example

Using the Union Operator (|)

Syntax

Return value

Example

Using "|=" Operator

Syntax

Example

Practice with Online Editor

﻿