#!/usr/bin/perl use strict; # https://perlmonks.org/?node_id=11144249 use warnings; open my $fh, '<', \< }; # slurp entire file my %solvent_face; $solvent_face{ "$3_$1" } = $2 while /\b (F\S+) \h+ ([-\d.]+) (?=.*? (\S+) \h+ 0.00000000 )/gsx; use Data::Dump 'dd'; dd \%solvent_face; #### { "acetonitrile_F002" => 1.69945785, "acetonitrile_F011" => 0.74578421, "acetonitrile_F101" => 2.67268035, "acetonitrile_F11-1" => 1.64808218, "acetonitrile_F111" => 1.95840198, "h2o_F002" => 4.66656083, "h2o_F011" => 26.13597035, "h2o_F101" => 32.47411476, "h2o_F11-1" => 29.58963453, "h2o_F111" => 30.24092207, }