[vox-tech] dumb perl question

[Jim Angstadt]

--- Peter Jay Salzman <p@dirac.org> wrote:
> the string that i'm matching though is $_, not
> $temperature.  $_ holds a
> filename, like "100.energy", and i'd like to extract
> the "100" from the
> filename and put it in $temperature.
> 
> doesn't
> 
> 	$temperature =~ s/(\d+).*/$1/;
> 
> assume that $temperature is the object holding
> "100.energy"?

Yes it does.

> 
> note that i'm being greedy here -- this DOES work:
> 
> 	/(\d+).*/;              # match "100" in $_
> 	$temperature = $+;      # put it in $temperature
> 
> i just want to do it in a single line.  :)   also,
> i'd like to do it
> without destroying the contents of $_ if possible.

Then your approach is the only way I know.  But, you
may want to take care of 'no match' cases.  $+ is the
last match.  If your match fails, then a prior match
will be picked up, *I think*.  (Not tested.)

One other point. the '.' is a metacharacter that
matches anything except a newline character.  So .*
matches the rest of the line.  It you want to match a
'.' then escape it:

# -----
use strict;
$_ = '100.energy';

/^(\d*)\./;
print "temp: $1\n";
# -----

Good luck.
Jim



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