Generating sets of array in perl

Question

Given perl script cut the input sequence at "E" and skips those particular positions of "E" which is mentioned in @nobreak, and generates an array of fragments as an output. But I want a script which generates set of such array in output for every position which has been skipped taking all positions of @nobreak into account. say set 1 contains fragments resulted after skipping at "E" 37, set 2 after skipping at "E" 45, and so on. Below mentioned script which I wrote is not working correctly. I want to generate 4 different array in output taking one position of @nobreak at a time. Please help!

my $s = 'MALWMRLLPLLALLALWGPDPAAAFVNQHLCGSHLVEALYLVCGERGFFYTPKTRREAEDLQVGQVELGGGPGAGSLQPLALEGSLQKRGIVEQCCTSICSLYQLENYCN';

print "Results of 1-Missed Cleavage:

";

my @nobreak = (37, 45, 57, 59);
{
    @nobreak = map { $_ - 1 } @nobreak;

    foreach (@nobreak) {

        substr($s, $_, 1) = "";
    } 
    my @a   = split /E(?!P)/, $s;
    $_      =~ s//E/g foreach (@a);
    $result = join "E,", @a; 
    @final  = split /,/, $result;
    print "@final
";
}

Answer 1

To split the string at every 'E' without consuming it in the process, use a lookbehind:

my @final = split /(?<=E)/, $str;

To assert finer control over which 'E' to split on (which you left unspecified), the change would be made to the regex.

In case a variable lookbehind is needed, one could use K...