Python Dictionary update() method (original) (raw)

Last Updated : 16 Feb, 2026

update() method in Python dictionary is used to add new key-value pairs or modify existing ones using another dictionary, iterable of pairs or keyword arguments. If a key already exists, its value is replaced. If the key does not exist, it is added to the dictionary.

**Example: In this example, another dictionary is used to update existing keys and add new keys.

Python `

d = {'A': 1, 'B': 2} d.update({'B': 5, 'C': 7}) print(d)

`

Output

{'A': 1, 'B': 5, 'C': 7}

**Explanation: d.update({'B': 5, 'C': 7}) replaces value of 'B' and adds 'C'.

Syntax

dict.update([other])

• **Parameters: other - Dictionary, iterable of key-value pairs, or keyword arguments.
• **Returns: Does not return anything. It updates the dictionary.

Examples

**Example 1: In this example, new key-value pairs are added to the dictionary.

Python `

d = {'x': 10} d.update({'y': 20}) print(d)

`

**Explanation: update({'y': 20}) adds new key 'y'.

**Example 2: In this example, the value of an existing key is modified.

Python `

d = {'a': 5, 'b': 8} d.update({'a': 50}) print(d)

`

**Explanation: update({'a': 50}) replaces old value of 'a'.

**Example 3: In this example, keyword arguments are used instead of another dictionary.

Python `

d = {'p': 1} d.update(q=2, r=3) print(d)

`

Output

{'p': 1, 'q': 2, 'r': 3}

**Explanation: update(q=2, r=3) adds keys using keywords.