如何在没有 len() 的情况下对列表中的项目进行操作？

Question

我正在尝试对列表中的每 5 个项目进行操作，但无法弄清楚如果剩余的项目没有平均分为 5 个如何处理。现在我正在使用模数，但是我无法摆脱这不是正确答案的感觉。这是一个例子...

list = ["ValA","ValB","ValC","ValD","ValE","ValF","ValG","ValH","ValI","ValJ","ValK","ValL","ValM","ValN",]
newlist = []
i = 0
for o in list:
  i += 1
  newlist.append(o)
  
  if i % 5 == 0:
    for obj in newlist:
      function_for(obj)
      newlist.clear()

此代码将执行 function_for() 两次，但不会执行第三次以处理剩余的 4 个值。如果我添加一条 'else' 语句，它会在每次执行时运行。

处理这种情况的正确方法是什么？

Answer 1

这种方法很简单，如果你不介意修改列表：

mylist = ["ValA","ValB","ValC","ValD","ValE","ValF","ValG","ValH","ValI","ValJ","ValK","ValL","ValM","ValN",]
while mylist:
     function_for( mylist[:5] )
     mylist = mylist[5:]

Answer 2

您还可以检查索引是否等于列表的长度。（此外，在这里使用 enumerate 而不是计数器变量更为惯用。）

lst = ["ValA","ValB","ValC","ValD","ValE","ValF","ValG","ValH","ValI","ValJ","ValK","ValL","ValM","ValN",]
newlist = []

for i, o in enumerate(lst, 1):
  newlist.append(o)
  if i % 5 == 0 or i == len(lst):
    print(newlist)
    newlist.clear()

如何在没有 len() 的情况下对列表中的项目进行操作？

How to handle operating on items in a list without perfectly even len()?

python

loops

modulo