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.")

Code Explanation:

Define the Function:

def key_exists(dictionary, key):

The function key_exists() takes two parameters:

dictionary: The dictionary in which to search for the key.

key: The key to check for.

Check for Key Presence:

if key in dictionary:

The in keyword is used to check if the key exists in the dictionary.

Return the Result:

return True

If the key exists, the function returns True, otherwise it returns False.

Example Dictionary:

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

A sample dictionary student is defined.

Specify Key to Check:

key_to_check = "age"

The variable key_to_check is assigned the value "age".

Call the Function and Print Result:

if key_exists(student, key_to_check):

The function is called to check if "age" exists in the student dictionary.

The output will be:

The key 'age' exists in the dictionary.