How to Add Value to Dictionary in Python

To add value to a dictionary in Python, you can use different methods like the = assignment operator, the update() function, or the setdefault() function.

The following examples show how to add value to a dictionary using different methods.

Using = Operator

We can use the assignment operator (=) to add a value to a dictionary.

Suppose we have the following dictionary:

# Create dictionary
dictionary1 = {"A": 25, "B": 27, "C": 45}

# Add value to dictionary
dictionary1["D"] = 36

# Show dictionary
print("Dictionary:", dictionary1)

Output: 👇️

Dictionary: {'A': 25, 'B': 27, 'C': 45, 'D': 36}

In this example, we use the assignment operator (=) to add the key-value pair “D”: 36 to the dictionary dictionary1.

Using update() Function

We can use the update() function to add a value to a dictionary.

Suppose we have the following dictionaries:

# Create dictionaries
dictionary1 = {"A": 25, "B": 27, "C": 45}
dictionary2 = {"D": 36}

# Add value to dictionary
dictionary1.update(dictionary2)

# Show dictionary
print("Dictionary:", dictionary1)

Output: 👇️

Dictionary: {'A': 25, 'B': 27, 'C': 45, 'D': 36}

In this example, we use the update() function to add the key-value pair from dictionary2 to dictionary1.

Using setdefault() Function

The setdefault() method adds a new key-value pair only if the key does not already exist. If the key already exists, it returns the existing value without modifying the dictionary.

Suppose we have the following dictionary:

# Create dictionary
dictionary1 = {"A": 25, "B": 27, "C": 45}

# Add value to dictionary
dictionary1.setdefault("D", 36)

# Show dictionary
print("Dictionary:", dictionary1)

Output: 👇️

Dictionary: {'A': 25, 'B': 27, 'C': 45, 'D': 36}

In this example, we use the setdefault() function to add the key-value pair “D”: 36 to the dictionary dictionary1.