Customizing Default Values for Input in Python

In Python, the default input command (input()) allows you to capture user input. However, you may want to provide a default value that the user can edit or accept.

Surprisingly, the standard input functions, input() and raw_input() lack this feature. Here's a solution that leverages the readline module.

The readline Module

If you're working in a Linux environment, you can utilize the readline module to create a custom input function. The readline module offers line editing and allows you to prefill the input field.

Defining a Custom Input Function

Here's how you can define a custom input function that takes a prompt and an optional prefill value:

import readline

def rlinput(prompt, prefill=''):
   readline.set_startup_hook(lambda: readline.insert_text(prefill))
   try:
      return input(prompt)  # or raw_input in Python 2
   finally:
      readline.set_startup_hook()

Usage

To use this custom input function, simply call it like this:

folder_name = rlinput('Folder name: ', 'Downloads')

This code will display a prompt asking for a folder name. It will initially display "Downloads" in the input field, and the user can edit it or press Enter to accept the default.