Split() on newline AND space characters?

Question

I want to split() a string on both newlines and space characters:

#!/usr/bin/perl
use warnings;
use strict;

my $str = "aa bb cc\ndd ee ff";
my @arr = split(/\s\n/, $str);     # Split on ' ' and '\n'
print join("\n", @arr);            # Print array, one element per line

Output is this:

aa bb cc
dd ee ff

But, what I want is this:

aa
bb
cc
dd
ee
ff

So my code is splitting on the newline (good) but not the spaces. According to perldoc, whitespace should be matched with \s in a character class, and I would have assumed that is whitespace. Am I missing something?

Answer 1

my code is splitting on the newline (good)

Your code is not splitting on newline; it only seems that way due to how you are printing things. Your array contains one element, not two. The element has a newline in the middle of it, and you are simply printing aa bb cc\ndd ee ff.

\s\n means: any whitespace followed by newline, where whitespace actually includes \n.

Change:

my @arr = split(/\s\n/, $str);

to:

my @arr = split(/\s/, $str);

Using Data::Dumper makes it clear that the array now has 6 elements:

use warnings;
use strict;
use Data::Dumper; 

my $str = "aa bb cc\ndd ee ff";
my @arr = split(/\s/, $str);
print Dumper(\@arr);

Prints:

$VAR1 = [
          'aa',
          'bb',
          'cc',
          'dd',
          'ee',
          'ff'
        ];

---

The above code works on the input string you provided. It is also common to split on multiple consecutive whitespaces using:

my @arr = split(/\s+/, $str);