How to Check if a Key Exists in a Dictionary using Python

Submitted by razormist on Thursday, January 9, 2025 - 23:52.

In this tutorial, we’ll learn how to program "How to Check if a Key Exists in a Dictionary Using Python." The objective is to safely check if a key currently exists in a dictionary. This tutorial will demonstrate the process of verifying whether a specific key is present in a dictionary. A sample program will be provided to guide you through the implementation. So, let’s get started!

This topic is simple to understand. Just follow the instructions I provide, and you’ll be able to complete it with ease. The program I’ll demonstrate will show you the correct way to check if a key exists in a dictionary. So, let’s start coding!

Getting Started:

First you will have to download & install the Python IDLE's, here's the link for the Integrated Development And Learning Environment for Python https://www.python.org/downloads/.

Creating Main Function

This is the main function of the application. The following code will display a simple GUI in terminal console that will display program. To do this, simply copy and paste these blocks of code into the IDLE text editor.

d = {'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
 
 
while True:
    print("\n================= Check if a Key Exists in a Dictionary =================\n\n")
    print(d)
    print("\n") 
    key = input("Enter a key: ")
    if key in d:
        print("Key already exist.")
    else:
        print("Key does not exist.")
 
    opt = input("\nDo you want to try again?(yes/no): ")
 
    if opt.lower() == 'yes':
        ret=False
    elif opt.lower() == 'no':
        ret=True
        print("Exiting program....")
    else:
        print("Please enter yes/no:")
        break
 
    if ret == False:
        continue

This program checks if a specified key exists in a dictionary. It starts with a predefined dictionary d = {'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}. The user is prompted to input a key. If the key exists in the dictionary, the program outputs "Key already exists." Otherwise, it outputs "Key does not exist." The process repeats in a loop until the user chooses to exit.

Output:

There you have it we successfully created How to Check if a Key Exists in a Dictionary using Python. I hope that this simple tutorial help you to what you are looking for. For more updates and tutorials just kindly visit this site. Enjoy Coding!

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