#!/your/perl/here

use strict;
use warnings;

my @accounts = ("A x1 B y1 C z1 D v1 E w1 F",
                "A x2 B y2 C zzz2 D v2 E w2 F",
                "A x3 B y3 C z3 D v3 E w3 F",
                "A x4 B y4 C  D v4 E wwww4 F", # note change to C..D
                "A x5 B y5 C z5 D v5 E w5 F",
                "A x6 B y6 C z6 D v6 E    F");

my @fields = ("A", "B", "C", "D", "E", "F");

my $regex = join '\s+(\w*)\s+', @fields;

my @accounts_2 = map {[/$regex/]} @accounts;

__END__