How to Check if an Expression Is Correctly Parenthesized in Python

Submitted by razormist on Sunday, February 22, 2026 - 23:10.

In this tutorial, we will learn how to program “How to Check if an Expression Is Correctly Parenthesized in Python.” The main objective is to determine whether a given expression has correctly balanced parentheses. This tutorial will guide you step by step through the process of analyzing the expression using a stack to verify that every opening parenthesis has a corresponding closing parenthesis in the correct order. By the end of this tutorial, you will have a clear understanding of how to check for balanced parentheses within a string, helping you strengthen your problem-solving abilities and improve your overall coding skills.

This topic is straightforward and easy to understand. By simply following the instructions provided, you will be able to complete it with ease. The program will guide you step by step through the process of checking whether an expression is correctly parenthesized. So, let’s dive into the coding process and start implementing the solution!

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.

class Stack:
    def __init__(self):
        self.items = []
 
    def is_empty(self):
        return self.items == []
 
    def push(self, data):
        self.items.append(data)
 
    def pop(self):
        return self.items.pop()
 
 
# MAIN LOOP
while True:
    print("\n============= Check if an Expression Is Correctly Parenthesized =============\n")
 
    s = Stack()
    exp = input('Please enter the expression: ')
 
    is_balanced = True  # assume balanced until proven otherwise
 
    for c in exp:
        if c == '(':
            s.push(1)
        elif c == ')':
            if s.is_empty():
                is_balanced = False
                break
            s.pop()
 
    if not s.is_empty():
        is_balanced = False
 
    if is_balanced:
        print('Expression is correctly parenthesized.')
    else:
        print('Expression is not correctly parenthesized.')
 
    # Ask user if they want to try again
    opt = input("\nDo you want to try again? (yes/no): ").strip().lower()
    if opt == "no":
        print("Exiting program...")
        break
    elif opt != "yes":
        print("Invalid choice. Exiting program...")
        break

This program checks whether a given expression is correctly parenthesized using a stack. It defines a simple `Stack` class with basic operations: push, pop, and checking if the stack is empty. The user inputs an expression, and the program iterates through each character. Every time it encounters an opening parenthesis `'('`, it pushes a marker onto the stack. For each closing parenthesis `')'`, it attempts to pop a marker from the stack. If the stack is empty when a closing parenthesis is encountered, or if any items remain in the stack after processing the entire expression, the expression is considered unbalanced. Otherwise, it is correctly parenthesized. The program repeats this process in a loop, allowing the user to check multiple expressions until they choose to exit.

Output:

There you have it we successfully created How to Check if an Expression Is Correctly Parenthesized in 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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