Write a function that checks whether a given key exists in a dictionary.

 def key_exists(dictionary, key):

    if key in dictionary:

        return True

    else:

        return False

student = {"name": "John", "age": 20, "grade": "A"}

key_to_check = "age"

if key_exists(student, key_to_check):

    print(f"The key '{key_to_check}' exists in the dictionary.")

else:

    print(f"The key '{key_to_check}' does not exist in the dictionary.")

#source code --> clcoding.com  

Code Explanation:

Define the Function

def key_exists(dictionary, key):

dictionary → This parameter represents the dictionary we want to check.

key → This is the key we are checking for inside the dictionary.

Check if the Key Exists

if key in dictionary:

    return True

else:

    return False

The in keyword checks if the given key exists inside the dictionary.

If the key is found, the function returns True.

If the key is not found, it returns False.

Example Usage

student = {"name": "John", "age": 20, "grade": "A"}

key_to_check = "age"

We create a dictionary called student.

We store "age" in key_to_check (this is the key we want to check).

Calling the Function

if key_exists(student, key_to_check):

    print(f"The key '{key_to_check}' exists in the dictionary.")

else:

    print(f"The key '{key_to_check}' does not exist in the dictionary.")

The function key_exists(student, key_to_check) is called.

If "age" exists in student, it prints:

The key 'age' exists in the dictionary.

If "age" was not in the dictionary, it would print:

The key 'age' does not exist in the dictionary.