$s = "I want to only show the first 100 characters or so of a string 
+that has more than 100, but I don't want to split it in the middle of
+ a word, so is there a way to do it instead of this:";;

print $string =~ m[(^.{0,100})\s];;
I want to only show the first 100 characters or so of a string that ha
+s more than 100, but I don't

print $s =~ m[(^.{0,$_})\s] for 20 .. 50;;
I want to only show
I want to only show
I want to only show
I want to only show the
I want to only show the
I want to only show the
I want to only show the
I want to only show the
I want to only show the
I want to only show the first
I want to only show the first
I want to only show the first
I want to only show the first
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100
I want to only show the first 100 characters
I want to only show the first 100 characters
I want to only show the first 100 characters
I want to only show the first 100 characters or
I want to only show the first 100 characters or
I want to only show the first 100 characters or
I want to only show the first 100 characters or so
[download]

That's the way I'd go too, but there's a little problem in your implementation:

$ perl -le'print "abc def" =~ m[(^.{0,100})\s]'
abc
[download]

Fix:

m[(^.{0,100})(?!\S)]
[download]

m[(^.{0,100})(\s|$)]
[download]

use strict;
use warnings;

my $s = "Hello, I am a perl/mysql programmer, but am self taught so I 
+do not know all the awesome features Perl has, however, I am ok at it
+ though, I guess.";

my $s2;
for (split /\s+/, $s) {
    $s2 .= "$_ ";
    last if length($s2) > 100;
}
print $s2;

__END__

Hello, I am a perl/mysql programmer, but am self taught so I do not kn
+ow all the awesome features Perl
[download]

Probably better as:

my $s2;
for ( split /(\s+)/, $s ) {
    last if length( $s2 . $_ ) > 100;
    $s2 .= $_;
}
print $s2;
[download]

In fact, your code is worse for 2 reasons:
• The output string $s2 no longer has any whitespace between words: Hello,Iamaperl/mysql...
• Generates a warning: Use of uninitialized value $s2...

use Text::Wrap;
$Text::Wrap::columns = 100;

my $truncated = (split /\n/, wrap("", "", $string))[0];
[download]

I modified your problem definition into:

How to split a string into several substrings (of a given maximum length) without breaking a word when splitting.

I found this (quickly hacked) solution:

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

my $text = "Hello, I am a perl/mysql programmer, but am self taught so
+ I do not know all the awesome features Perl has, however, I am ok at
+ it though, I guess.";

sub split_at {
    my ( $text, $len ) = @_;
    my @result;

    my @parts = split /[ ]/, $text;

    my $short = shift @parts;
    while ( @parts ) {
        if ( length($short) + length($parts[0]) < $len ) {
            $short = join( ' ', $short, shift @parts );
        }
        else {
            push @result, $short;
            $short = shift @parts;
        }
    }

    push @result, $short;

    return @result;
}


{
    local $, = local $\ = $/;
    print split_at( $text, 100 );

    # beware
    print split_at( 'a'x110, 100 );
}
[download]

Limitation: If the given string doesn't contain any whitespace (\x20), it won't split at all.

If you just want/need the first substring, just use the first returned element.

Updates:

if ( length($short) + length($parts[0]) <= $len ) {
    $short = join( ' ', $short, shift @parts );
}
[download]

The length is off by one because you add not only the part, but a new space as well. The easy fix is to delete the = from <= $len

($string) = ("$string " =~ m{(.{1,100}\s)});
[download]

I don't see how that's ever useful. If the string has less than 100 characters, it returns nothing. If the string has 100 or more characters, it returns either the same as the OP's solution or too many characters. (I'm assuming 100 is a maximum, such as a screen width or a field width.)

You've also used a different definition of "word" than everyone else such that cutting "don't" into "don" and "'t" is acceptable, and so is cutting "don't" into "don'" and "t".

Ah... the original post said 'around 100 characters' not that that was the maximum. But no matter.

Sigh. I suppose I did commit the cardinal sin of posting Sloppy code.

And, I should have been clear that what I posted was NOT a turnkey solution but a suggestion that a regex approach might make sense.

so... OK, below is the result of another few minutes fiddling, this will work better, certainly.

my $string;
$string = 'lasdufaner%.alsdfi,' x 100;
# $string = 'freddy\'s wife wilma, ' x 100;

my $max  = 100;

if ( $string and length $string > $max ){
   $string = substr( $string, 0, $max);
   my ($tmp) = $string =~ /(.+)\s.*?$/; # last space if possible
   $tmp or ($tmp) = $string =~ /(.+)\W.*?$/; # bust on last non-word
   $tmp and $string = $tmp;
   print $string
}
[download]


freddy's wife output:
freddy's wife wilma, freddy's wife wilma, freddy's wife wilma, freddy's wife wilma, freddy's wife

lasd... output
lasdufaner%.alsdfi,lasdufaner%.alsdfi,lasdufaner%.alsdfi,lasdufaner%.alsdfi,lasdufaner%.alsdfi

The point being, I suppose, that this sort of thing might be easily handled by a regular expression in most cases.

Thanks for your comment though, it's always good to have a second set of eyes. :-)

\s