use strict;
use warnings;
use Data::Dumper;

my @array=('GAP_SPAN09 - GAP SPAN base (Scratch Testing [TSMC11] : tsmc11_wld(sxfatd12j)) GAP_SPAN03 - GAP SPAN base (DFD E2E Testing [TSPAN04] : tspan04-dfdint-wld(sxfamd6f)) POS_WLI02 - POS_WLI02 Web Logic Integrator');

my @newarray;
while ($array[0] =~ /(\w+) - /g) {
    push @newarray, $1;
}
print Dumper(\@newarray);

__END__

$VAR1 = [
          'GAP_SPAN09',
          'GAP_SPAN03',
          'POS_WLI02'
        ];