Sending Multiple Inputs to a Lua Script Using Subprocess in Python

What will you learn?

In this comprehensive guide, you will learn how to seamlessly send multiple inputs to a Lua script using Python’s subprocess module. By mastering this technique, you will enhance your automation skills and effectively communicate with external scripts.

Introduction to the Problem and Solution

Encountering scenarios where Python applications need to interact with scripts written in languages like Lua is common. The challenge lies in establishing efficient communication between these distinct environments. To address this challenge, we leverage the subprocess module in Python.

By utilizing subprocess, we can execute Lua scripts from Python and transmit various data inputs to the script. This not only expands the capabilities of your application but also exemplifies a robust approach to cross-language collaboration.


import subprocess

# Path to your Lua script
lua_script_path = 'path/to/your/script.lua'

# Multiple inputs you want to send
inputs = ['input1', 'input2', 'input3']

# Opening a subprocess and passing inputs via stdin
with subprocess.Popen(['lua', lua_script_path], stdin=subprocess.PIPE,
                      text=True) as proc:
    for input_data in inputs:
        proc.stdin.write(input_data + "\n")

# Copyright PHD


The code snippet demonstrates how subprocess.Popen function can be used to execute an external command (Lua script) from Python. It involves creating a new process, sending input data, and handling text-based communication effectively.

  • Subprocess Creation: Utilize subprocess.Popen to establish communication with an external process.

  • Sending Inputs: Iterate over input data list and write each item into the process’s standard input.

  • Process Lifecycle: Manage the process lifecycle within the context manager, ensuring proper handling of input data.

    1. How do I install Lua on my system? Lua can typically be installed using package managers like apt-get on Ubuntu or brew on macOS. Refer to official documentation for precise instructions.

    2. Can I receive output back from my Lua script? Yes, by capturing stdout using stdout=subprocess.PIPE.

    3. What if my inputs are dynamic? The provided example handles dynamic inputs efficiently at runtime.

    4. Is error handling necessary? Robust error handling including checking exit status is crucial for production-quality code.

    5. Can I pass arguments directly when calling Popen? Yes, arguments passed after ‘lua’ act as CLI arguments accessible within your Lua script.


By mastering the art of interfacing between Python applications and LUA scripts using subprocess, you unlock endless possibilities for enhancing project functionality. Efficiently applying these techniques in your developments ensures increased efficiency and adaptability of solutions crafted.

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