In [9]: i=0 
   ...: while(i<len(lst)): 
   ...:     if lst[i]==2: 
   ...:         del lst[i] 
   ...:     else: 
   ...:         i+=1 
   ...: print(lst) 
   ...:                                                                                        
[1, 3, 4, 5]

还是老老实实循环吧