Compare lists for differences

Question

I'm trying to create a text editor based in my python interpreter. The environment is sandboxed so I can't use my file system or command line. I have input working, I just need to figure out how to update the screen.

import os, sys, tty

# Active text file
text = [''] * int(os.environ.get('PS_TTY_ROWS'))

# Cursor position
cursor = cursor_x, cursor_y = 1, 1

# Allow instant recipt of inputs
tty.setraw(sys.stdin)
sys.stdout.write('\033[H\033[J')

# Main input loop
while True:
    key = sys.stdin.read(1)
    sys.stdout.write('\033[H' + str(text))
    if key == '\x1b':
        key = sys.stdin.read(2)
        if key == '[A': # Up
            cursor_y = sorted((1, len(text) - 1, cursor_y - 1))[1]
        elif key == '[B': # Down
            cursor_y = sorted((1, len(text) - 1, cursor_y + 1))[1]
        elif key == '[C': # Right
            cursor_x = sorted((1, len(text[cursor_y - 1]) + 1, cursor_x + 1))[1]
        elif key == '[D': # Left
            cursor_x = sorted((1, len(text[cursor_y - 1]) + 1, cursor_x - 1))[1]
    elif key == '\x7f': # Backspace
        if cursor_x > 1:
            text = ('\r'.join(text[:cursor_y - 1]) + '\r' + text[cursor_y - 1][:cursor_x - 2] + text[cursor_y - 1][cursor_x - 1:] + '\r' + '\r'.join(text[cursor_y:])).split('\r')
            cursor_x -= 1
    else:
        text[cursor_y - 1] = text[cursor_y - 1][:cursor_x - 1] + key + text[cursor_y - 1][cursor_x - 1:]
        cursor_x = sorted((1, len(text[cursor_y - 1]) + 1, cursor_x + 1))[1]
        if key == '\r':
            cursor_y += 1
            cursor_x = 1
    text = '\r'.join(text).split('\r')
    sys.stdout.write('\033[J\033[H' + '\n'.join(text[:min(len(text), int(os.environ.get('PS_TTY_ROWS')) - 1)]))
    sys.stdout.write('\033[' + str(cursor_y) + ';' + str(min(len(text[cursor_y - 1]) + 1, cursor_x)) + 'H')

My current method of redrawing the entire screen on refresh but it is a bit slower than I'd like and I'm hoping to replace it with a method of only redrawing what's changed, is there a way to compare two lists (a copy of the text before input and the text list after input) for changes to see what to redraw without using loops or list comprehensions?