awk: compare fields of file 1 to fields of file 2

beca123456 · 04-30-2016, 05:48 PM

Hi,

Using awk, I am trying to append the comment(s) of file2 at the end of file1 if:
- field1 of file1 is equal to field1 of file2
AND
- field2 of file1 is ≥ field2 of file2 and ≤ field3 in file2

file1.tab (NF is constant):

Code:

1   20   value1
4   73   value2

file2.tab (NF is variable):

Code:

1   10   30   commentA1   commentA2
2   50   89   commentB1
4   55   90   commentC1

output:

Code:

1   20   value1   commentA1   commentA2
4   73   value2   commentC1

I can (kind of) output the first condition (i.e. if $1 file1 = $2 file2), but don't see how to do deal with the second condition:

Code:

gawk 'BEGIN{FS="\t"}NR==FNR{a[$1]=$0; next}{print $0 FS a[$1]}' file2 file1

which produces:

Code:

1   20   value1   1   10   30   commentA1   commentA2
4   73   value2   4   55   90   commentC1

syg00 · 04-30-2016, 08:03 PM

First you'd better get your head around the first condition. You aren't testing for equality of anything, let alone $1. Also, saving into the array like that will replace (i.e. lose) previous records if $1 in file2 is not unique. And once saved, field-splitting on the saved data is no longer in effect.
Take it one step at a time.

grail · 05-01-2016, 03:28 AM

The other issue I see is that file2 seems to be able to have a variable number of comments and as these are the only things you need to keep, you need a way to append all but the first 3 fields.

As syg00 has said, you need to take this one step at a time. I would ignore file1 for the time being and work out how to store all the required information from file2.