Python Tutorials

Python Programs

How to Add a Key-Value Pair to a Dictionary in Python


How to Add a Key-Value Pair to a Dictionary in Python ?

Answer

To add a key-value pair to a dictionary in Python, you can use the dictionary's key assignment or the `update` method.



✐ Examples

1 Adding a Key-Value Pair Using Key Assignment

We can add a key-value pair to a dictionary in Python using key assignment. This example demonstrates how to add key-value pairs to a dictionary and print its contents.

For example,

  1. We start by declaring and initializing an empty dictionary named my_dict.
  2. We add key-value pairs to the dictionary using key assignment.
  3. We print the dictionary contents to verify the key-value pairs.

Python Program

my_dict = {}

# Add key-value pairs to the dictionary
my_dict[1] = 'One'
my_dict[2] = 'Two'
my_dict[3] = 'Three'

# Print the dictionary contents
print('Dictionary contents:')
for key, value in my_dict.items():
    print(f'Key: {key}, Value: {value}')

Output

Dictionary contents:
Key: 1, Value: One
Key: 2, Value: Two
Key: 3, Value: Three

2 Adding Multiple Key-Value Pairs Using the `update` Method

We can add multiple key-value pairs to a dictionary in Python using the `update` method. This example demonstrates how to add key-value pairs to a dictionary using the `update` method and print its contents.

For example,

  1. We start by declaring and initializing an empty dictionary named my_dict.
  2. We add key-value pairs to the dictionary using the `update` method.
  3. We print the dictionary contents to verify the key-value pairs.

Python Program

my_dict = {}

# Add key-value pairs to the dictionary using the update method
my_dict.update({
    'A': 1.1,
    'B': 2.2,
    'C': 3.3
})

# Print the dictionary contents
print('Dictionary contents:')
for key, value in my_dict.items():
    print(f'Key: {key}, Value: {value}')

Output

Dictionary contents:
Key: A, Value: 1.1
Key: B, Value: 2.2
Key: C, Value: 3.3

Summary

In this tutorial, we learned How to Add a Key-Value Pair to a Dictionary in Python language with well detailed examples.




More Python Dictionaries Tutorials

  1. How to create an Empty Dictionary in Python ?
  2. How to create a Dictionary with Initial Key-Value Pairs in Python ?
  3. How to Print a Dictionary in Python ?
  4. How to Add a Key-Value Pair to a Dictionary in Python ?
  5. How to Set a Default Value for a Key in a Dictionary in Python ?
  6. How to Update the Value for a Key in a Dictionary in Python ?
  7. How to Check if a Dictionary is Empty in Python ?
  8. How to Check if a Key Exists in a Dictionary in Python ?
  9. How to Check if a Value Exists in a Dictionary in Python ?
  10. How to Get the Value Associated with a Key in a Dictionary in Python ?
  11. How to Remove a Key-Value Pair from a Dictionary in Python ?
  12. How to Remove Key-Value Pairs from a Dictionary Based on Values in Python ?
  13. How to Clear all Key-Value Pairs from a Dictionary in Python ?
  14. How to Iterate over Keys in a Dictionary in Python ?
  15. How to Iterate over Values in a Dictionary in Python ?
  16. How to Iterate over Entries (Key-Value Pairs) in a Dictionary in Python ?
  17. How to Get the Size (Number of Key-Value Pairs) of a Dictionary in Python ?
  18. How to Convert a Dictionary to an Array of Keys in Python ?
  19. How to Convert a Dictionary to an Array of Values in Python ?
  20. How to Convert a Dictionary to an Array of Key-Value Pairs in Python ?
  21. How to Merge Two Dictionaries in Python ?
  22. How to Clone a Dictionary in Python ?
  23. How to Check if Two Dictionaries are Equal in Python ?
  24. How to Sort a Dictionary by Keys in Python ?
  25. How to Sort a Dictionary by Values in Python ?
  26. How to Filter a Dictionary Based on Keys in Python ?
  27. How to Filter a Dictionary Based on Values in Python ?
  28. How to Reduce Values in a Dictionary to a Single Value in Python ?
  29. How to Convert an Array of Key-Value Pairs to a Dictionary in Python ?
  30. How to Convert a Dictionary to a JSON String in Python ?
  31. How to Convert a JSON String to a Dictionary in Python ?
  32. How to Swap Keys and Values in a Dictionary in Python ?
  33. How to Create a Dictionary of Dictionaries in Python ?
  34. How to Iterate Over a Dictionary of Dictionaries in Python ?