📘 Overview

Python is a versatile language with powerful libraries for creating Graphical User Interfaces (GUIs). One of the most beginner-friendly and widely used is Tkinter — it comes bundled with Python and provides all the basic tools to build windows, buttons, input fields, and more.

In this first article, we’ll cover:

What is a UI in Python?

Introduction to Tkinter

Creating your first GUI window

Adding widgets: Labels, Buttons, and Entry

Handling events with functions

🧠 What is a UI in Python?

A User Interface (UI) allows users to interact with software through graphical elements like windows, buttons, text fields, etc., instead of typing commands.

Python supports many UI libraries:

Tkinter – built-in and beginner-friendly

PyQt – feature-rich, better for complex UIs

Kivy – used for multitouch apps and mobile support

Dear PyGui, PySide, and others...

We’ll start with Tkinter, then explore others in future parts.

🧱 Adding Widgets: Labels, Buttons, and Entry

Let’s add some common UI elements:

✅ Step 2: Label + Entry + Button

import tkinter as tk def greet_user(): username = entry.get() label_result.config(text=f"Hello, {username}!") root = tk.Tk() root.title("Greeting App") root.geometry("300x150") label_prompt = tk.Label(root, text="Enter your name:") label_prompt.pack(pady=5) entry = tk.Entry(root) entry.pack(pady=5) button_greet = tk.Button(root, text="Greet", command=greet_user) button_greet.pack(pady=5) label_result = tk.Label(root, text="") label_result.pack(pady=5) root.mainloop()

🧠 What’s happening here:

Label shows text.

Entry allows input.

Button triggers a function (greet_user()).

config() updates the label text dynamically.

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🧮 Build a Calculator in Python Using Lambda & Tkinter

Creating a calculator is a great way to learn about Python functions, GUI programming, and event handling. In this tutorial, we’ll build a simple calculator using lambda functions for operations and Tkinter for the user interface.

📦 What You’ll Learn

How to use lambda functions for basic operations
How to build a Tkinter GUI
How to wire up buttons with actions dynamically

🛠️ Prerequisites

Python 3.x installed
Basic knowledge of Python functions and Tkinter

You can install Tkinter (if not already installed) using:

pip install tk

Note: Tkinter comes pre-installed with most Python distributions.

🔣 Step-by-Step: Create a Lambda-Based Calculator

✅ Step 1: Import Tkinter

import tkinter as tk
from functools import partial

✅ Step 2: Define Operations Using Lambda

operations = {
    '+': lambda x, y: float(x) + float(y),
    '-': lambda x, y: float(x) - float(y),
    '*': lambda x, y: float(x) * float(y),
    '/': lambda x, y: float(x) / float(y) if float(y) != 0 else "Error"
}

✅ Step 3: Create the GUI Window

root = tk.Tk()
root.title("Lambda Calculator")
root.geometry("300x300")

✅ Step 4: Create Input Fields and Result Display

entry1 = tk.Entry(root, width=10)
entry1.grid(row=0, column=0, padx=10, pady=10)

entry2 = tk.Entry(root, width=10)
entry2.grid(row=0, column=1, padx=10, pady=10)

result_label = tk.Label(root, text="Result: ")
result_label.grid(row=1, column=0, columnspan=2)

✅ Step 5: Define a Generic Operation Handler

def calculate(op):
    try:
        val1 = entry1.get()
        val2 = entry2.get()
        result = operations[op](val1, val2)
        result_label.config(text=f"Result: {result}")
    except Exception as e:
        result_label.config(text="Error")

✅ Step 6: Create Buttons for Operations

row = 2
col = 0

for symbol in operations:
    action = partial(calculate, symbol)
    tk.Button(root, text=symbol, width=5, command=action).grid(row=row, column=col, padx=5, pady=5)
    col += 1

✅ Step 7: Run the Application

root.mainloop()

🖥️ Full Working Code

Here’s the full code for your reference:

import tkinter as tk
from functools import partial

# Define lambda operations
operations = {
    '+': lambda x, y: float(x) + float(y),
    '-': lambda x, y: float(x) - float(y),
    '*': lambda x, y: float(x) * float(y),
    '/': lambda x, y: float(x) / float(y) if float(y) != 0 else "Error"
}

# Create the window
root = tk.Tk()
root.title("Lambda Calculator")
root.geometry("300x300")

# Entry widgets
entry1 = tk.Entry(root, width=10)
entry1.grid(row=0, column=0, padx=10, pady=10)

entry2 = tk.Entry(root, width=10)
entry2.grid(row=0, column=1, padx=10, pady=10)

# Result label
result_label = tk.Label(root, text="Result: ")
result_label.grid(row=1, column=0, columnspan=2)

# Calculation function
def calculate(op):
    try:
        val1 = entry1.get()
        val2 = entry2.get()
        result = operations[op](val1, val2)
        result_label.config(text=f"Result: {result}")
    except Exception:
        result_label.config(text="Error")

# Buttons for operations
row = 2
col = 0
for symbol in operations:
    action = partial(calculate, symbol)
    tk.Button(root, text=symbol, width=5, command=action).grid(row=row, column=col, padx=5, pady=5)
    col += 1

# Run the app
root.mainloop()

📚 Summary

Lambda functions let us define concise, anonymous operations.
Tkinter helps us build user interfaces with minimal code.
This calculator is fully functional and can be expanded to support more features like clearing fields or advanced operations.

Would you like to watch video explanation to create a calculator using python Lambda ? watch video below:

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Learn Python

Menu

Python GUI Tutorial for Beginners – Create Simple UIs with Tkinter

🐍 Python UI Programming Series — Part 1: Getting Started with Tkinter

📘 Overview

🧠 What is a UI in Python?

🧰 Why Tkinter?

🖼️ Your First GUI with Tkinter

✅ Step 1: Basic Window

🧱 Adding Widgets: Labels, Buttons, and Entry

✅ Step 2: Label + Entry + Button

💡 Recap

🚀 Coming Up in Part 2:

Build a Simple Python Calculator Using Lambda and Tkinter (Step-by-Step Guide)