Attach frequent words in text file - perl

Question

I have two files. The first contains frequent
word sequences
extracted from a text file
a.txt :
big pizza
eat big pizza
...
the text file is
b.txt :
i eat big pizza .my big pizza ...
My problem is to add bbb between words from each sequence that exist in file a.txt and write a new file .
so the result will be
i eatbbbbigbbbpizza.my bigbbbpizza...
below is my script. It adds bbb only between pairs 9f words. How can I correct this?
use strict;
use warnings;
use autodie;
my ($f1, $f2) = ('a.txt', 'b.txt');
open( my $fh, $f1 );
my #seq;
foreach ( <$fh> ) {
chomp;
s/^\s+|\s+$//g;
push #seq, $_;
}
close $fh;
open($fh, $f2);
foreach (<$fh> ) {
foreach my $r (#seq) {
my $t = $r =~ s/ /bbb/r;
if (/$r/) {
s/$r/$t/g;
}
}
print ;
}
close $fh;

Answer 1

All that is wrong is your line
my $t = $r =~ s/ /bbb/r;
This substitution runs just once, and so replaces only the first space with bbb
You need to use a global substitution instead. And while we're changing this line it's best to also replace the space with \h+, which matches any amount of "horizontal space", including both tabs and spaces
my $t = $r =~ s/\h+/bbb/gr;
As it stands your code will find and replacing substrings of other entries in #seq if they appear earlier in the array. In this case, that means big pizza will be found first and converted to bigbbbpizza, after which
eat big pizza can no longer be found. You need to first sort your array in descending order of length so that longer phrases are found before shorter ones
#seq = sort { length($b) <=> length($a) } #seq;
Then your program will work a little better

Answer 2

Here is the modified code.
use strict;
use warnings;
use autodie;
my ($f1, $f2) = ('a.txt', 'b.txt');
open(my $fh, $f1);
my #seq;
foreach (<$fh> )
{
chomp;
s/^\s+|\s+$//g;
push #seq, $_;
}
close $fh;
#seq = sort bylen #seq; # need to sort #seq by length.
open($fh, $f2);
foreach (<$fh> ) {
foreach my $r (#seq) {
my $t = $r =~ s/ /bbb/gr;
s/$r/$t/g; # you may need to take care of cases of extra spaces
}
print;
}
close $fh;
exit 0;
sub bylen {
length($b) <=> length($a);
}