custom comparison function generator for sorted in Python

mycmp.py

import numpy as np
from random import random

def cmp0(d):
    def cmp(a,b):
        return int(a[d]-b[d])
    return cmp

def cmp1(dd):
    def cmp(a,b):
        for d in dd:
            x,y=a[d],b[d]
            if x!=y: return int(x-y)
        return 0
    return cmp

def dig(x,dd):
    for d in dd:
        x=x[d]
    return x

def cmp2(ddd):
    def cmp(a,b):
        for dd in ddd:
            x,y=dig(a,dd),dig(b,dd)
            if x!=y: return int(x-y)
        return 0
    return cmp

def mycmp(dims,order='asc'):
    dims=np.array(dims)
    if dims.dtype!=np.dtype('int') or not np.all(dims>=0):
        raise 'mycmp: dims should be array of positive int'
    D=len(dims.shape)
    if D>=3:
        raise 'mycmp: depth of dims should be less than 3'
    cmp=[cmp0,cmp1,cmp2][D](dims)
    if order=='asc':
        return cmp
    if order=='desc':
        return lambda b,a: cmp(a,b)
    raise 'mycmp: order should be "asc" or "desc"'

if __name__ == '__main__':
    
    xx=[[int(random()*5)
        for i in range(3)]
        for j in range(5)]
    
    xxx=[[[int(random()*5)
        for i in range(3)]
        for j in range(5)]
        for k in range(7)]
    
    print 'DATA xx:'
    print xx
    print ''
    
    print 'DATA xxx:'
    print xxx
    print ''
    
    print 'TEST CASE 1: xx,mycmp(1)'
    yy=sorted(xx,cmp=mycmp(1))
    for y in yy: print y
    print ''
        
    print 'TEST CASE 2: xx,mycmp([1,2])'
    yy=sorted(xx,cmp=mycmp([1,2]))
    for y in yy: print y
    print ''
    
    print 'TEST CASE 3: xxx,mycmp([[1,2]])'
    yyy=sorted(xxx,cmp=mycmp([[1,2]]))
    for yy in yyy: print yy
    print ''

    print 'TEST CASE 4: xxx,mycmp([[0,1],[1,2]])'
    yyy=sorted(xxx,cmp=mycmp([[0,1],[1,2]]))
    for yy in yyy: print yy
    print ''

    #
    # actually, the code above can be replaced with below
    # we can specify some functions returning numeric tuple
    #
    
    print 'TEST CASE A: xx,lambda x: x[1]'
    yy=sorted(xx,key=lambda x: x[1])
    for y in yy: print y
    print ''
        
    print 'TEST CASE B: xx,lambda x: (x[1],x[2])'
    yy=sorted(xx,key=lambda x: (x[1],x[2]))
    for y in yy: print y
    print ''
    
    print 'TEST CASE C: xxx,lambda x: x[1][2]'
    yy=sorted(xxx,key=lambda x: x[1][2])
    for yy in yyy: print yy
    print ''

    print 'TEST CASE D: xxx,lambda x: (x[0][1],x[1][2])'
    yyy=sorted(xxx,key=lambda x: (x[0][1],x[1][2]))
    for yy in yyy: print yy
    print ''