python常规方法实现数组的全排列

def perm(l):  if(len(l)<=1):    return [l]  r=[]  for i in range(len(l)):    s=l[:i]+l[i+1:]    p=perm(s)    for x in p:      r.append(l[i:i+1]+x)  return r

if __name__=='__main__':   """ default param is list(1,2,3,4,5) """  l=[];   if(len(sys.argv)<=1):     """input=['%d' %(i) for i in xrange(1,6)]"""    l=list((1,2,3,4,5))  else:#input param looks like "2,3,4,5,6",no legal checks here.    input=str(sys.argv[1])    l=input.split(",")     for i in xrange(len(l)):       l[i] = int(l[i])   print perm(l)