Python Dictionary

Python Dictionary

Dictionary is a collection of key:value pairs.

Python Dictionary

In a dictionary, keys are unique. Each key has an associated value. You can access value using key in a Dictionary.

Create a Dictionary

In Python, Dictionary can be created using curly brackets and comma separated key:value pairs.

Following is an example of initializing or creating a Python Dictionary with three key:value pairs.

myDictionary = {
	"name": "Lini",
	"year": 1989,
	"expertise": "data analytics"}

Where myDictionary variable holds the dictionary. You can use this variable name to access the items of the dictionary or call dictionary related functions.

Print Dictionary

You can use print() function to print dictionary to console. Dictionary is converted to a String constant and then printed.

In the following program, we will create a dictionary and print the dictionary to console.

Python Program

myDictionary = {
	"name": "Lini",
	"year": 1989,
	"expertise": "data analytics"}

print(myDictionary)

Explanation

  1. A dictionary myDictionary is created with three key-value pairs: "name": "Lini", "year": 1989, and "expertise": "data analytics".
  2. The print() function is used to display the entire dictionary on the console.
  3. The output will be the dictionary in its key-value pair format: {'name': 'Lini', 'year': 1989, 'expertise': 'data analytics'}.

Output

{'name': 'Lini', 'year': 1989, 'expertise': 'data analytics'}

The dictionary is printed as a single string.

To know about printing dictionary key:value pairs, keys, or values, refer Python Print Dictionary.

Check if given Python object is a dictionary

You can check the type of the dictionary variable, if it is actually a dictionary. Use type() function as shown below. type() function returns the class type of variable.

Python Program

myDictionary = {
	"name": "Lini",
	"year": 1989,
	"expertise": "data analytics"}

print(type(myDictionary))

Explanation

  1. A dictionary myDictionary is created with three key-value pairs: "name": "Lini", "year": 1989, and "expertise": "data analytics".
  2. The type() function is used to determine the type of myDictionary.
  3. The print() function is used to display the type of the dictionary on the console.
  4. The output will be <class 'dict'>, indicating that myDictionary is a dictionary object.

Output

<class 'dict'>

<class 'dict'> means dictionary class. dict is shorthand for dictionary.

Loop through key:value pairs in given dictionary

Dictionary is a collection of items. You can loop through these items using a looping technique.

In this example, we will write a Python program to traverse through key:value pairs of a Dictionary using Python For Loop.

Python Program

myDictionary = {
	"name": "Lini",
	"year": 1989,
	"expertise": "data analytics"}

for key, value in myDictionary.items():
	print(key, ': ', value)

Explanation

  1. A dictionary myDictionary is created with three key-value pairs: "name": "Lini", "year": 1989, and "expertise": "data analytics".
  2. The items() method is called on myDictionary, which returns a view object containing key-value pairs as tuples.
  3. A for loop is used to iterate through the dictionary, where key and value represent the current key and corresponding value in each iteration.
  4. The print() function is used to display each key followed by its value, separated by a colon. The output will be:
    • name : Lini
    • year : 1989
    • expertise : data analytics

Output

name :  Lini
year :  1989
expertise :  data analytics

Summary

In this tutorial of Python Examples, we learned how to create a Dictionary in Python, how to print a Dictionary to console, how to check if a Python object is a dictionary or not.



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