santa.py

#!/usr/bin/env python

from __future__ import print_function

import numpy as np
import time

def clear():
    print(chr(27) + "[2J")

mapping = {}

clear()
try:
    while True:
        name, number = None, None
        while not name:
            name = raw_input('Please enter your name: ')
        while number is None:
            try:
                number = int(raw_input('Please enter your number: '))
            except ValueError:
                print("That's not a number.")
            if number in mapping:
                print('That number is already taken.')
                number = None

        mapping[number] = name

        signal = raw_input('Thank you!\nPress ENTER to clear the screen, or type \'END\' to finish. ')
        if signal == 'END':
            break
        clear()
except EOFError:
    pass

clear()


name_length = max([len(name) for name in mapping.values()])

while True:
    presents = set(mapping.keys())
    new_mapping = {}
    try:
        for number, name in mapping.items():
            n = np.random.choice(list(presents - set([number])))
            presents -= set([n])
            new_mapping[n] = name
    except ValueError:
        continue
    break

for number, name in new_mapping.items():
    print('{} {}'.format((name + ':').ljust(name_length + 1), number))