Choose from a range interactively

choice.py

#!/usr/bin/env python3
# choice.py, by Sean B. Palmer

import sys

countries = ["Albania", "Andorra", "Austria", "Belarus", "Belgium", "Bulgaria",
"Cyprus", "Czechoslovakia", "Denmark", "Estonia", "Faeroe Islands", "Finland",
"France", "Germany", "Gibraltar", "Greece", "Guernsey", "Hungary", "Iceland",
"Ireland", "Isle of Man", "Italy", "Jan Mayen", "Jersey", "Latvia",
"Liechtenstein", "Lithuania", "Luxembourg", "Malta", "Moldova", "Monaco",
"Netherlands", "Norway", "Poland", "Portugal", "Romania", "San Marino",
"Spain", "Sweden", "Switzerland", "United Kingdom", "Yugoslavia"]

write = sys.stdout.write

# http://stackoverflow.com/a/21659588
def _find_getch():
    try: import termios
    except ImportError:
        # Non-POSIX. Return msvcrt's (Windows') getch.
        import msvcrt
        return msvcrt.getch

    # POSIX system. Create and return a getch that manipulates the tty.
    import tty
    def _getch():
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(fd)
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch

    return _getch

getch = _find_getch()

def select(items, pattern):
    if not pattern:
        return items[:]
    return [item for item in items if pattern in item]

def format(items, pattern, position):
    selected = select(items, pattern)
    try:
        selected_item = selected[position]
        selected[position] = "*%s*" % selected[position]
        # selected = selected[position:]
    except IndexError:
        selected_item = None
    output = pattern + ": " + ", ".join(selected)
    if len(output) > 79:
        output = output[:76].rstrip(", ")
        output += "..."
    write("\r")
    write(output + (" " * (79 - len(output))))
    sys.stdout.flush()
    return len(selected), selected_item

def choose(choices):
    pattern = ""
    position = 0
    count, selected = format(choices, pattern, position)
    cancelled = False
    while True:
        ch = getch()
        # print(repr(ch))
        if ch in {"\x03", "\x04"}: # C-c C-d
            cancelled = True
            break
        elif ch in {"\n", "\r"}:
            break
        elif ch == "\x1b":
            a = getch()
            b = getch()
            if (a == "[") and (b == "C"): # Right Arrow
                if position < (count - 1):
                    position += 1
            elif (a == "[") and (b == "D"): # Left Arrow
                if position > 0:
                    position -= 1
        elif ch == "\x7f":
            if pattern:
                pattern = pattern[:-1]
        elif ch.isprintable():
            pattern += ch
        count, selected = format(choices, pattern, position)
    if not cancelled:
        print()
        return selected
    else:
        print()
        return None

def main():
    selection = choose(countries)
    print("Selection:", selection)

if __name__ == "__main__":
    main()