Utility for sudoku

sudoku_utils.py

## Tests
import time, random

def from_file(filename, sep='\n'):
    "Parse a file into a list of strings, separated by sep."
    return file(filename).read().strip().split(sep)

def parse_grid(gridstr):
    gridstr = gridstr.replace('\n', '')
    return [[int(gridstr[i+9*j]) for i in range(9)] for j in range(9)]

def solve_all(solve_sudoku, grids, name='', showif=0.0):
    times = []
    for grid in grids:
        start = time.clock()
        assert solve_sudoku(parse_grid(grid)), "Could not solve grid: %s" % grid
        t = time.clock() - start
        if showif is not None and t > showif:
            print "board: %s took %.2f s" % (grid, t)
        times.append(t)
    N = len(grids)
    if N > 1:
        print "%d boards took total %.2f s, avg %.2f s, (%.2f Hz), max %.2f s" % (N, sum(times), sum(times)/N, N/sum(times), max(times))
    return True