So if I have a given information line and I'm trying to index each line but the way they overlap prevents generalizing indexes (first line being 123 3455 then the second line being 1234567 12) how can I categorize the first two numbers with the same name holder?

ie:

```
fo = open file
for line in fo:
    first_number = line[0:3]

```

this doesn't work because for the second line the number is a lot longer, but how would I index the numbers to the white space after the first number?