First word

[Anonymous Monk]

Hey guys, I have a string $x in a scalar, and I need to copy the first 'word' of string to $y and I can't seem to find anywhere how to do it. I know that \w would be the regex for a 'word' and know how to match it, but how do I capture it in another variable without having to split the whole string then just copy $x[0]. Many thanks, Bill

[FunkyMonk]

Step-by-step:

match a single word character	/\w/
match a word	/\w+/
match a word at the start	/^\w+/
capture it	/^(\w+)/
bind the pattern to a string	$x =~ /^(\w+)/
assign captured word	my ( $word ) = $x =~ /^(\w+)/

The parentheses around $word are important.

Update: Reformatted

[andreas1234567]

Like this?

$ perl -l
use warnings;
use strict;
my $x = "hey dude what's up";
(my $y = $x) =~ s/(\w+).*/$1/;
print $y;
__END__
hey

[Anonymous Monk]

Winner winner, chicken dinner! (saw the movie 21 last night, it comes highly recommended). Yes thats perfect! Just so I can make sense of it and use it in future, any chance you could explain s/(\w+).*/$1/ Thanks again, it's perfect.

[toolic]

You can read all about the Substitution Operator in the free online documentation at perlretut. Search for "Search and replace". There are dazzling multi-color code examples complete with hyperlinks!

Or, if you prefer reading from a book, Learning Perl is a good place to start.

[cdarke]

I know that \w would be the regex for a 'word'

I suppose that depends on what you mean by a 'word'. \w is [A-Za-z0-9_], it includes numerics and the underscore. As noted, \b is a word boundary, although sometimes matches in unexpected places like apostrophies - "Clive's house" will appear to be 3 words.

[haoess]

$ perl -wle 'print shift =~ /^(\w+)\b/' "That's my sentence."
That

As you can see, \w matches a word character, and \b marks the end of the first word (since we're matching the beginning aka ^ of the string).

More information at perlre.

-- Frank

[grizzley]

You don't need \b because \w+ is greedy.

[jeepj]

you could also use split (There's more than one way to do it)

$y=split(/\s/,$x)[0];

Update: at first, it sounds a good solution, but I'm not sure after all...