How do I split a string at a char position that's also the end of a word?

holly has asked for the wisdom of the Perl Monks concerning the following question:

I'm new to perl so this is probably going to end up being a simple and stupid problem, but I was just trying to write a script that would take a text file and add newlines after 80 chars or the end of the nearest word. Here's what I've got, but it ain't workin':

foreach $line (@file)
{
  $line =~ s/\s\b{70}/$1\n/g);
}
[download]

If anyone has any advice, I'd love to hear it!

thanks,
Holly

edit:replaced pre-tag with code-tag (neophyte, 2001-08-27)

Comment on How do I split a string at a char position that's also the end of a word? Download Code

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Re: How do I split a string at a char position that's also the end of a word? by japhy (Canon) on Aug 27, 2001 at 15:17 UTC
The problem is that `\b` matches a location, and not actual text. I have a feeling you'll want to write something like: `s/(.{0,80})\b/$1\n/g for @file;` [download] This will match up to 80 (non-newline) characters, and try to match a word boundary after them. If it can't, it'll back up one character and try again. _____________________________________________________ Jeff`[japhy]`Pinyan: Perl, regex, and perl hacker. `s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;`	[reply] [d/l]
Re (tilly) 1: How do I split a string at a char position that's also the end of a word? by tilly (Archbishop) on Aug 27, 2001 at 16:07 UTC
When you have written your script, I would suggest rewriting it using the CPAN module Text::Autoformat. The experience should show you why it is good to use CPAN when you can. :-)	[reply]
Re: How do I split a string at a char position that's also the end of a word? by MZSanford (Curate) on Aug 27, 2001 at 15:13 UTC
hmmm, wrapping text ... i would think (untested): `foreach my $line (@file) { $line =~ s/(.{70}\B{1,10})/$1\n/g); }` [download] you are not working because of a few things. the ones which stick out are the missing parens in the first half of the `s///`, which define `$1`. The other is the `\b{70}`, which looks for 70 word boudries in a row. While my solution may not work, these are a few things that might help you find the way. My version gobbles 70 chars, then starts looksing for boundries over the next 10 chars. A better way would be to read 80 chars, then back track to the last word boudry, or, see Text::Wrapper _{can't sleep clowns will eat me} -- MZSanford	[reply] [d/l] [select]
Re: How do I split a string at a char position that's also the end of a word? by htoug (Deacon) on Aug 27, 2001 at 16:28 UTC
Use the Text::Wrap module, in the core for newer perls, or on CPAN.	[reply]
Re: How do I split a string at a char position that's also the end of a word? by lshatzer (Friar) on Aug 27, 2001 at 18:09 UTC
I had to do something similar, and used rindex instead, check out Truncate string. Or as suggested, Text::Autoformat and Text::Wrap.	[reply]