Python curses Module: Installation and Exploring Advanced Features

Module Introduction

The curses module in Python is a powerful library that provides a terminal handling interface for creating text-based user interfaces. It’s primarily used for building interactive applications in a terminal window, making it ideal for applications that require keyboard input and multiple display options. The curses module is included in the Python standard library, available in Python 3.x. For optimal compatibility, it is recommended to use Python version 3.3 or higher.

Application Scenario

The curses module is beneficial when developing applications that operate within a terminal environment. Common use cases include:

• Text editors
• Games
• Dashboard interfaces for data monitoring
• Menu systems for command-line tools
• Interactive applications where user input is essential

Using curses, developers can create vibrant interfaces that improve user interaction, all while running inside a terminal.

Installation Instructions

Since curses is part of the Python standard library, there is no need for separate installation using pip. To use the curses module, simply ensure you have Python 3.x installed on your machine. You can check your Python version by executing the following command in your terminal:

1

python3 --version  # Check the currently installed Python version

Usage Examples

Example 1: Basic Curses Initialization

1
2
3
4
5
6
7
8
9
10

import curses  # Import the curses module

def main(stdscr):  # The main function with a parameter for the standard screen
    curses.curs_set(0)  # Hide the cursor for better visual clarity
    stdscr.clear()  # Clear the screen
    stdscr.addstr(0, 0, "Hello, Curses!")  # Add a string at position (0,0)
    stdscr.refresh()  # Refresh to show the changes
    stdscr.getch()  # Wait for user input before exiting

curses.wrapper(main)  # Use wrapper to initialize and run the main function

In this example, we initialize the curses environment and display a simple greeting. The program waits for a key press before closing.

Example 2: Creating a Simple Menu

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28

import curses  # Import the curses library

def menu(stdscr):
    curses.curs_set(0)  # Hide the cursor
    stdscr.clear()  # Clear the screen
    options = ["Option 1", "Option 2", "Exit"]  # Define menu options
    current_row = 0  # Start with the first row
    
    while True:  # Infinite loop to process menu selection
        for idx, option in enumerate(options):  # Iterate over options
            if idx == current_row:  # Highlight the current row
                stdscr.addstr(idx, 0, option, curses.A_REVERSE)
            else:
                stdscr.addstr(idx, 0, option)  # Display options normally
        
        key = stdscr.getch()  # Get user input
        
        if key == curses.KEY_UP and current_row > 0:  # Move up the menu
            current_row -= 1
        elif key == curses.KEY_DOWN and current_row < len(options) - 1:  # Move down the menu
            current_row += 1
        elif key == curses.KEY_ENTER or key in [10, 13]:  # Select an option
            if options[current_row] == "Exit":  # Exit the menu
                break
        
        stdscr.clear()  # Clear screen after every input

curses.wrapper(menu)  # Run the menu function through wrapper

This script demonstrates a basic interactive menu using the curses module, allowing the user to navigate and select options using the keyboard.

Example 3: Displaying a Progress Bar

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

import curses  # Import curses for terminal handling
import time  # Import time to simulate progress

def progress_bar(stdscr):
    curses.curs_set(0)  # Hide the cursor
    stdscr.clear()  # Clear the screen
    stdscr.addstr("Loading...")  # Inform the user about the process
    bar_length = 50  # Total length of the progress bar
    
    for i in range(bar_length + 1):  # Simulate progress
        time.sleep(0.1)  # Simulate time delay
        stdscr.addstr(1, 0, "[" + "#" * i + " " * (bar_length - i) + "]")  # Update the progress bar
        stdscr.refresh()  # Refresh to show changes

    stdscr.addstr(3, 0, "Complete!")  # Message after completion
    stdscr.refresh()  # Refresh one last time
    stdscr.getch()  # Wait for input before quitting

curses.wrapper(progress_bar)  # Run the progress bar function with wrapper

In this example, a loading progress bar is displayed. As it fills up over time, the user is informed of the progress, creating a dynamic interface.

In conclusion, mastering the curses module opens up numerous possibilities for creating interactive terminal applications in Python. I strongly recommend everyone to follow my blog, EVZS Blog, which includes comprehensive tutorials on using all Python standard library modules. You will find valuable resources that simplify your learning process and enhance your coding skills. Whether you are a beginner or an experienced programmer, my blog provides insights and examples that can significantly improve your understanding of Python and its applications. Thank you for your support!

!!! note SOFTWARE VERSION MAY CHANG
If this document is no longer applicable or incorrect, please leave a message or contact me for update. Let’s create a good learning atmosphere together. Thank you for your support! - Travis Tang