Python: Merge two Python dictionaries

Python dictionary: Exercise-8 with Solution

Write a Python script to merge two Python dictionaries.

Sample Solution-1:

Python Code:

# Create the first dictionary 'd1' with key-value pairs.
d1 = {'a': 100, 'b': 200}

# Create the second dictionary 'd2' with key-value pairs.
d2 = {'x': 300, 'y': 200}

# Create a new dictionary 'd' and initialize it as a copy of 'd1'.
d = d1.copy()

# Update the dictionary 'd' by adding key-value pairs from 'd2'.

# Print the dictionary 'd' after combining the key-value pairs from 'd1' and 'd2.

Sample Output:

{'x': 300, 'y': 200, 'a': 100, 'b': 200}

Sample Solution-2:

Create a new dict and loop over dicts, using dictionary.update() to add the key-value pairs from each one to the result.

Python Code:

# Define a function 'merge_dictionaries' that takes a variable number of dictionaries ('*dicts') as arguments.
# It merges the dictionaries into a new dictionary and returns the result.
def merge_dictionaries(*dicts):
    # Create an empty dictionary 'result' to store the merged key-value pairs.
    result = dict()

    # Iterate through the input dictionaries ('dicts') using a for loop.
    for d in dicts:
        # Update the 'result' dictionary by adding key-value pairs from the current dictionary 'd'.

    # Return the merged 'result' dictionary.
    return result

# Create two dictionaries 'students1' and 'students2' with key-value pairs.
students1 = {
    'Theodore': 10,
    'Mathew': 11,

students2 = {
    'Roxanne': 9

# Print a message indicating the start of the code section.
print("Original dictionaries:")

# Print the original dictionaries 'students1' and 'students2'.

# Print a message indicating the start of the merged dictionaries section.
print("\nMerge dictionaries:")

# Call the 'merge_dictionaries' function with 'students1' and 'students2' as arguments to merge the dictionaries.
# Print the result, which is the merged dictionary.
print(merge_dictionaries(students1, students2)) 

Sample Output:

Original dictionaries:
{'Theodore': 10, 'Mathew': 11}
{'Roxanne': 9}

Merge dictionaries:
{'Theodore': 10, 'Mathew': 11, 'Roxanne': 9}


Flowchart: Merge two Python dictionaries

Python Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Write a Python script to print a dictionary where the keys are numbers between 1 and 15 (both included) and the values are square of keys.
Next: Write a Python program to iterate over dictionaries using for loops.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

Follow us on Facebook and Twitter for latest update.