Show Default Value for Editing on Python Input Possible

Show default value for editing on Python input possible?

The standard library functions input() and raw_input() don't have this functionality. If you're using Linux you can use the readline module to define an input function that uses a prefill value and advanced line editing:

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()

Is it possible to create an input with an editable default value?

You can test whether the user has inputted anything then if they haven't replace it:

default_val = 'Default answer'
inp = input("Enter a string (default value is: '"+default_val+"'): ")
if not inp:
    inp = default_val
print(inp)

This outputs:

Enter a string (default value is: 'Default answer'): 
Default answer

or

Enter a string (default value is: 'Default answer'): Different answer
Different answer

Python: Get user input by letting user edit default value

Yes, there is a way. Use readline

import readline

defaultText = 'I am the default value'
readline.set_startup_hook(lambda: readline.insert_text(defaultText))
res = raw_input('Edit this:')
print res

Note that this is not a terribly portable solution, and I've only tested it on Linux :)

Pre-initialize raw_input with default value

I actually found an answer myself after some more Googling. It can be done with raw_input when using the readline module as follows:

import readline

def pre_input_hook():
    readline.insert_text('DefaultValue')
    readline.redisplay()

readline.set_pre_input_hook(pre_input_hook)

while True:
    line = raw_input('Prompt ("stop" to quit): ')
    if line == 'stop':
        break
    print 'ENTERED: "%s"' % line

Or, to wrap it all in an easier-to-handle function based on jonrsharpe's comment:

import readline

DEFAULT_TEXT = ''

def default_hook():
    """Insert some default text into the raw_input."""
    readline.insert_text(default_hook.default_text)
    readline.redisplay()

readline.set_pre_input_hook(default_hook)

def raw_input_default(prompt, default=None):
    """Take raw_input with a default value."""
    default_hook.default_text = DEFAULT_TEXT if default is None else default
    return raw_input(prompt)

python console, better than raw_input(), how to offer editable default values?

I suggest looking into readline / pyreadline, or even possibly curses.

How to give the user pre-filled input to edit and then approve? Python

We can do this in a Tkinter window. Which may not be what you are looking for, but is a solution using the standard library. Here is some example code that creates a window with a default string. You can edit the string. When the return key is pressed, the string in the window is read.

from tkinter import Tk, LEFT, BOTH, StringVar
from tkinter.ttk import Entry, Frame

class Example(Frame):
    def __init__(self, parent):
        Frame.__init__(self, parent)
        self.parent = parent
        self.initUI()

    def initUI(self):
        self.parent.title("Entry")
        self.pack(fill=BOTH, expand=1)
        self.contents = StringVar()
        # give the StringVar a default value
        self.contents.set('test')
        self.entry = Entry(self)
        self.entry.pack(side=LEFT, padx=15)
        self.entry["textvariable"] = self.contents
        self.entry.bind('<Key-Return>', self.on_changed)

    def on_changed(self, event):
        print('contents: {}'.format(self.contents.get()))
        return True

def main():
    root = Tk()
    ex = Example(root)
    root.geometry("250x100+300+300")
    root.mainloop()

if __name__ == '__main__':
    main()

---

Related Topics