How python handle iteration in blank-CodePudding

Why python doesn't raise an error when I try do this, instead it print Nothing.

empty = []
for i in empty:
    for y in i:
        print(y)

Is that python stop iterate it the first level or it just iterates over and print None?

I found this when trying to create a infinite loop but it stop when list become empty

CodePudding user response：

Your list variable empty is initialized with empty list. so, the first iteration itself will not enter, since the list is empty.

CodePudding user response：

Since the list is empty, the loop will not run at all.

CodePudding user response：

There is nothing to iterate over in empty list. Hence, for loop won't run even for a single time. However, if it is required to get an error for this you can raise an exception like below:

empty = []
if len(empty) == 0:
    raise Exception("List is empty")
for i in empty:
    for y in i:
        print(y)