CODEWITHSUNDEEP
perlforeach
user221014
user221014

Reputation:

Why doesn't my Perl code work when I put it in a foreach loop?

This code outputs the scalars in the row array properly:

  $line = "This is my favorite test";
  @row = split(/ /, $line);

  print $row[0];
  print $row[1];

The same code inside a foreach loop doesn't print any scalar values:

  foreach $line (@lines){
      @row = split(/ /, $line);
      print $row[0];
      print $row[1];
  }

What could cause this to happen?

I am new to Perl coming from python. I need to learn Perl for my new position.

Upvotes: 2

Views: 1003

Answers (2)

brian d foy
brian d foy

Reputation: 132811

When I run into these sorts of problems where I wonder why something in a block is not happening, I add some debugging code to ensure I actually enter the block:

 print "\@lines has " . @lines . " elements to process\n";
 foreach my $line ( @lines )
      {
      print "Processing [$line]\n";
      ...;
      }

You can also do this in your favorite debugger by setting breakpoints and inspecting variables, but that's a bit too much work for me. :)

If you need to learn Perl and already know Python, you shouldn't have that much trouble going through Learning Perl in a couple of days.

Upvotes: 1

cikkle
cikkle

Reputation: 458

As already mentioned in Jefromi's comments, whatever the problem is, it exists outside of the code you posted. This works entirely fine:

$lines[0] = "This is my favorite test";

foreach $line (@lines) {
    @row = split(/ /, $line);
    print $row[0];
    print $row[1];
}

The output is Thisis

Upvotes: 3

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