Whenever you start a new block of text, set all flags (defined below) to zero.
3. If the next line starts with KEGG I want all lines until 'function evidence' to be written as a block without "KEGG pathway (this part works in my code). if this part is absent I want to write 'unknown' (need help).
Define "part". The line starting "KEGG"? A line starting with "KEGG" that doesn't have a pathway?

If you find the desired "part", set $kegg to 1.

When you hit "function evidence", set $kegg to zero.

Whenever you read a line, if $kegg is set to 1, print it out.

4. Then there should be descriptions for 'function evidence', 'process evidence', and 'component evidence'(in the same order). If any one of these are missing, 'unknown' needs to be written in place of that (need help).
Set a flag when each of the key phrases is encountered. When a line is a key phrase, and the flag is set, display "unknown". Otherwise, display the contents of the line. Clear the flag.

In reply to Re: parsing multiple lines by apl
in thread parsing multiple lines by sm2004

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