Python dictionary update value if the key exists | Example code

Use the “in” keyword to check if keys exist. If exist then update the value of the dictionary in Python. If the key exists, we update its value by assigning a new value to the key using the assignment operator (=).

Example dictionary update value if the key exists in Python

Simple example code update value for a given key in the dictionary.

d = {"key1": 10, "key2": 23}

if "key2" in d:
    d.update({"key2": 20})

print(d)

Output:

If the key does not exist in the dictionary, assigning a new value to it will create a new key-value pair in the dictionary.

my_dict = {"key1": "value1", "key2": "value2"}

if "key3" in my_dict:
    my_dict["key3"] = "new_value3"

print(my_dict)

Do comment if you have any doubts or suggestions on this Python dictionary update topic.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.