Simple puzzle (Installation of click package needed - with pip)

puzzle.py

import click
from random import shuffle

blocks = ['1', '2', '3', '4', '5', '6', '7', '8', '-']

def init_puzzle():
    shuffle(blocks)
    flat_puzzle = blocks
    puzzle = [[0 for j in range(3)] for i in range(3)]
    for i in range(3):
        for j in range(3):
            puzzle[i][j] = flat_puzzle[i * 3 + j]

    return puzzle


def draw_puzzle(puzzle):
    for i in range(3):
        print ' '.join(puzzle[i])
    print '-----'

def find_dash(puzzle):
    for i in range(3):
        for j in range(3):
            if puzzle[i][j] == '-':
                return i, j


def up(puzzle):
    i, j = find_dash(puzzle)
    if i == 0:
        return
    prev = puzzle[i-1][j]
    puzzle[i-1][j] = '-'
    puzzle[i][j] = prev
    
def down(puzzle):
    i, j = find_dash(puzzle)
    if i == 2:
        return
    prev = puzzle[i+1][j]
    puzzle[i+1][j] = '-'
    puzzle[i][j] = prev

def right(puzzle):
    i, j = find_dash(puzzle)
    if j == 2:
        return
    prev = puzzle[i][j+1]
    puzzle[i][j+1] = '-'
    puzzle[i][j] = prev

def left(puzzle):
    i, j = find_dash(puzzle)
    if j == 0:
        return
    prev = puzzle[i][j-1]
    puzzle[i][j-1] = '-'
    puzzle[i][j] = prev


def main():
    puzzle = init_puzzle()
    while True:
        draw_puzzle(puzzle)
        key = ord(click.getchar()[2])
        if key == 65:
            up(puzzle)

        elif key == 66:
            down(puzzle)

        elif key == 68:
            left(puzzle)

        elif key == 67:
            right(puzzle)

main()