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)