Outer nested loop not working when taking file input

Question

Here is the code

f = open("mmk.tsv")
g = f
for a in f:
    print("-")
    for b in g:
        print("+")

The output is only one "-" and several "+"s.

When I remove the inner loop the outer loop works as expected.

You need to be more specific about the problem you're facing, so that the community can help you. In this case, are you trying to parse a tab-seperated file? — a'r, May 16 '20 at 10:59

score 1 · Answer 1 · answered May 16 '20 at 11:00

1

You can only iterate over a file once. Doing it through different variables doesn't change that.

Read file file into a list, then you can have multiple iterations.

with open("mmk.tsv") as f:
    lines = f.readlines()
for a in lines:
    print("-")
    for b in lines:
        print("+")

answered May 16 '20 at 11:00

Barmar

_You can only iterate over a file once. Doing it through different variables doesn't change that_ it's just confusing – Kurohige May 16 '20 at 11:06

1 Answers1