Re^4: How to loop over two lines, alter a value in the current line and save it to the previous line?

I'm afraid I don't understand, by $previous_line always being the first line it affects all of the variables in the loop. The loop starts on line 2, with the previous line being line 1; in the next iteration I'd like it to be on line 3, with the previous line being line 2 (and so on).

Comment on Re^4: How to loop over two lines, alter a value in the current line and save it to the previous line?

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Re^5: How to loop over two lines, alter a value in the current line and save it to the previous line? by hdb (Monsignor) on Jan 07, 2016 at 11:59 UTC
Why do you need `$previous_line` if you already have `@previous_columns`?	[reply] [d/l] [select]
Re^6: How to loop over two lines, alter a value in the current line and save it to the previous line? by rjc33 (Sexton) on Jan 07, 2016 at 12:09 UTC
Apologies, I should have said that it makes the values within @previous_columns always refer to those in the first line. So for example in the 2nd iteration of the loop @previous_columns holds values from the first line, when I want to hold values from the second line (while the loop is performing actions on the 3rd line).	[reply]