Perl output successive string from array

Question

I have an array I can print out as "abcd" however I am trying to print it as "a>ab>abc>abcd". I can't figure out the nested loop I need within the foreach loop I have. What loop do I need within it to print it this way?

my $str = "a>b>c>d";
my @words = split />/, $str;

foreach my $i (0 .. $#words) {
print $words[$i], "\n";
}

Thank you.

Answer 1

You had the right idea, but instead of printing the word at position i, you want to print all the words between positions 0 and i (inclusive). Also, your input can contain multiple strings, so loop over them.

use warnings;

while (my $str = <>) {              # read lines from stdin or named files
  chomp($str);                      # remove any trailing line separator

  my @words = split />/, $str;      # break string into array of words
  foreach my $i (0 .. $#words) {
    print join '', @words[0 .. $i]; # build the term from the first n words
    print '>' if $i < $#words;      # print separator between terms (but not at end)
  }

  print "\n";
}

There are many other ways to write it, but hopefully this way helps you understand what's happening and why. Good luck!

Answer 2

one liner:

perl -e '@a=qw(a b c d); for(@a) {$s.=($h.=$_).">"} $s=substr($s,0,-1);print $s'