Creating scientific calculator using Python Tkinter and Flask

Creating a scientific calculator using Python with a Tkinter GUI and a Flask API is an exciting project that covers multiple topics like GUI development, web APIs, and mathematical operations. The post provides step-by-step instructions for setting up the project with code examples.

Table of Contents

• Prerequisite:
• Step 1: Create Flask API
• Step 2: Create Tkinter GUI
• Step 3: Run Both Programs
• FAQ

Prerequisite:

• Install falsk restful : https://pypi.org/project/Flask-RESTful/
• Understanding of Rest API
• Understanding of Python 3.x

pip install Flask-RESTful

Step 1: Create Flask API

In the first step, you create a Flask API by writing code that handles POST requests with JSON data. The code extracts the operation, num1, and num2 from the request, performs the corresponding mathematical operation, and returns the result in JSON format.

Create a new Python file named calculator_api.py and write the following code:

from flask import Flask, request, jsonify

app = Flask(__name__)

@app.route('/calculate', methods=['POST'])
def calculate():
    try:
        data = request.json
        operation = data['operation']
        num1 = float(data['num1'])
        num2 = float(data['num2'])

        if operation == 'add':
            result = num1 + num2
        elif operation == 'subtract':
            result = num1 - num2
        elif operation == 'multiply':
            result = num1 * num2
        elif operation == 'divide':
            if num2 == 0:
                return jsonify({'error': 'Cannot divide by zero'})
            result = num1 / num2
        else:
            return jsonify({'error': 'Invalid operation'})

        return jsonify({'result': result})

    except Exception as e:
        return jsonify({'error': str(e)})

if __name__ == '__main__':
    app.run(port=3000)

Step 2: Create Tkinter GUI

Next, you create a Tkinter GUI by writing code that creates an interface with input fields for num1, num2, and a dropdown menu for selecting the desired operation. There is also a button that triggers the calculation when clicked. The GUI code uses the requests library to send a POST request to the Flask API, passing the operation and numeric inputs. The response is then displayed in a label below.

Create another Python file named calculator_gui.py and write the following code:

import tkinter as tk
from tkinter import ttk
import requests

def make_calculation():
    num1 = float(entry1.get())
    num2 = float(entry2.get())
    operation = operation_var.get()

    data = {'operation': operation, 'num1': num1, 'num2': num2}

    response = requests.post('http://localhost:3000/calculate', json=data)
    result = response.json()

    if 'error' in result:
        output_label.config(text=f"Error: {result['error']}")
    else:
        output_label.config(text=f"Result: {result['result']}")

# GUI
root = tk.Tk()
root.title('Scientific Calculator')

entry1 = ttk.Entry(root)
entry1.grid(row=0, column=1)
entry2 = ttk.Entry(root)
entry2.grid(row=1, column=1)

operation_var = tk.StringVar()
operation_var.set('add')

operations = ['add', 'subtract', 'multiply', 'divide']

operation_menu = ttk.OptionMenu(root, operation_var, *operations)
operation_menu.grid(row=2, column=1)

calculate_button = ttk.Button(root, text='Calculate', command=make_calculation)
calculate_button.grid(row=3, column=1)

output_label = ttk.Label(root, text='Result:')
output_label.grid(row=4, column=1)

root.mainloop()

Step 3: Run Both Programs

Finally, running both programs simultaneously to use the calculator. You start the Flask API by running the calculator_api.py file and then run the calculator_gui.py file to launch the Tkinter GUI. The GUI allows you to enter numbers and select an operation, and it displays the calculated result.

1. Run calculator_api.py to start the Flask API.
2. Run calculator_gui.py to start the Tkinter GUI.

To use the calculator, enter numbers in the Tkinter GUI and select the operation you want to perform. Then, click “Calculate”. The result should appear below.

FAQ

What is Flask?

Flask is a micro web framework for Python used to develop web applications, including RESTful APIs. It is known for its simplicity and flexibility.

How do I create a basic Flask API?

To create a basic Flask API, you need to define routes and functions that handle HTTP requests. You can use decorators like @app.route('/') to specify the URL route.

What is RESTful API and how does Flask support it?

A RESTful API follows the principles of Representational State Transfer (REST). Flask supports RESTful API development by allowing you to define routes for different HTTP methods (GET, POST, PUT, DELETE) and use them to perform CRUD operations on resources.

Is Flask suitable for building large-scale APIs?

Flask can be used to build APIs of various sizes, but for large-scale applications, you may consider using additional libraries and structuring your project appropriately.