Assistance with building regex - regex

Question

I hate doing this but I've banged my head for hours just trying to figure out regexes, so I am finally resorting to asking the experts.
-1,AAABO,ABOAO
-2,ABBBO,BABBO
-3,AAACO,ACAAO
-4,ABDDO,BADDO
-5,AAABF,ABFAA
-6,BBBGO,BGBBO
I am looking to match multiple substrings but only between the commas.
For example:
AA and B would return rows 1,5
BB and O would return 2 and 6
BBB and G would return row 6
AA C and O would return row 3
I would build this dynamically as needed.
The 2nd step would be filtering on the beginning or end of the string after the 2nd comma
For example (start):
AB would return row 1 and 5
For example (end):
BO would return row 2 and 6
and then I need to combine all 3 filters.
For example
AAA O (contains from 2nd column)
AB (begins with)
O (ends with)
returns row 1
I could do multiple passes if required.
I would be delighted with any guidance.

Answer 1

You want the regex
/^.*?,(?=[^,]*AAA)(?=[^,]*O).*?,AB.*O$/
with commentary
/
^.*?, # consume the first field
(?=[^,]*AAA) # look ahead in the 2nd field for AAA
(?=[^,]*O) # look ahead in the 2nd field for O
.*?, # consume the 2nd field
AB.*O$ # the 3rd field starts with AB and ends with O
/x
which you can generate like this
sub gen_regex {
my ($begins, $ends, #contains) = #_;
my $regex = "^.*?,"
. join("", map {"(?=[^,]*$_)"} #contains)
. ".*?,$begins.*$ends\$";
return qr/$regex/;
}
my $re = gen_regex('AB', 'O', qw(AAA O));
and then use it like this:
while (<>) { say $. if /$re/ }