Split and Pattern Match

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

Up front I must apologize for the trivial questions but I'm 2 years out of practice and have no Perl experts around to help.

First:
I need to split up a string on white space:
$var = "1 word here another word";

the "1 word here" needs to be split from "another word". I've tried several things with switch and split but nothing works. Also, once they are split up, how do I remove the white space either before or after the values. For example:
"1 word here " down to "1 word here" and
" another word" down to "another word"

Second:
I need to evaluate the first two positions of a string to see if they're numeric. I cannot remember how to specify to only look at certain positions in a string and nothing else. How is that done?

Thanks in advance for your help.
You guys rock!

Comment on Split and Pattern Match

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Re: Split and Pattern Match by particle (Vicar) on Jun 06, 2003 at 15:47 UTC
`my( @list )= spilt '' => $var;` this trims whitespace automatically. check perlfunc for more on `split` `$var =~ m/ \A ## beginning of string \d{2} ## two digit characters /x` [download] see perlre and perlretut for more on regular expressions. ~Particle accelerates	[reply] [d/l] [select]
Re: Split and Pattern Match by broquaint (Abbot) on Jun 06, 2003 at 15:46 UTC
Here's a regex solution to your first query `my $var = "1 word here another word"; my($head, $tail) = $var =~ /( (?:\w+[ ]?){3} ) [ ] (.*)/x; print "head - [$head]\n"; print "tail - [$tail]\n"; __output__ head - [1 word here] tail - [another word]` [download] For your second quandary we'll use another splashing of regex `print "yup" if "12 buckle my shoe" =~ /^\d{2}\b/; __output__ yup` [download] See. `perlre` for more info on the regexes used above. HTH `_________ broquaint`	[reply] [d/l] [select]
Re: Split and Pattern Match by hardburn (Abbot) on Jun 06, 2003 at 15:43 UTC
I need to split up a string on white space `my $var = "1 word here another word"; my @words = split /\s+/, $var;` [download] Also, once they are split up, how do I remove the white space either before or after the values. `my $var = ' some words '; $var =~ s/\A \s* (.) \s \z /$1/x;` [download] ---- I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident. -- Schemer Note: All code is untested, unless otherwise stated	[reply] [d/l] [select]
Re: Split and Pattern Match by djantzen (Priest) on Jun 06, 2003 at 15:54 UTC
Does "1 word here another word" mean you have word pairs like "foo bar", "baz quux", or "foo bar baz quux"? Assuming the former, you can break that up like so: `my $var = "foo bar"; my @vals = split ' ', $var; # if you need something more complex, use +a regex for the pattern` [download] Note that if you split on the whitespace it will already be stripped from the returned strings, so no extra processing should be necessary. For the second question, a match will do the trick: `foreach my $val (@vals) { print "Numeric\n" if $val =~ /^[0-9]{2}/; }` [download] Alternatively you could use substr. "The dead do not recognize context" -- Kai, Lexx	[reply] [d/l] [select]
Re: Split and Pattern Match by wfbojar (Initiate) on Jun 06, 2003 at 16:29 UTC
Thanks for the help. The white space did not come out on my orriginal post. It was supposed to be $var = "1 word here _______________________ another word"; where the underscores are spaces. Thanks again.	[reply]