badrinath chitrala wrote:
Hi

Hello,

open FILE, "file.txt" or die $!;

open() creates the filehandle FILE which is associated with the contents of
the file "file.txt".

while (<f:/file.txt>)

You are using a file glob to get a list of file names which is the same as doing:

while ( defined( $_ = glob 'f:/file.txt' ) )

You want to use the newly created filehandle instead:

while ( <FILE)

Which is the same as:

while ( defined( $_ = <FILE) )

Which reads from the contents of the file.

perldoc -f open
perldoc perlopentut
perldoc -f readline
perldoc perlop (I/ section)

John

Mon, May 08, 2006 at 08:07:56AM -0700, Xuning Wang wrote:

Hi:

I have a question about replacing $ sign when it is
before a digit. For example:

$str = "$1.12";

I want to extact the dollar amount 1.12 from $str.

If I do this:
$str =~ s/\$//;

$str then become .12. The "$1" in "$1.12" is
interpreted first before substitution is applied. How
do I prevent this? I can't use this:
$str ='$1.12' because the $1.12 is read from a file.

Does anyone have a suggestion?

Something else is going on, but I can't say exactly where.

$ echo '$1.12' | perl -ple 's/\$//'
1.12

Perhaps you have some other interpolation going on where you don't need
it?

Mon, May 08, 2006 at 08:35:52AM -0700, Xuning Wang wrote:

Thanks for reply. The question is easily solvable if
it is in the same file as the perl script. You can use
single quotes or backslash to modify the string.

But as I stated in the message, the "$1.12" was in a
text file along with other things, say you have a
sentence like this in a file: Apple $1.12. You can't
modify the file itself. So it's hard to utilize "\" or
use single quotes because you have to first read the
sentence from a file.

And my example, which you will find below since you top posted and I
can't be bothered to rearrange things, shows the equivalent of reading
from a file with nary a backslash in sight, save the one you used in the
substitution.

Paul Johnson <paul (AT) pjcj (DOT) netwrote:

Something else is going on, but I can't say exactly where.

$ echo '$1.12' | perl -ple 's/\$//'
1.12

Perhaps you have some other interpolation going on where you don't
need it?

5/8/06, Xuning Wang <jasonxw (AT) yahoo (DOT) comwrote:

Subject: Unsolvable? How to extract

"Unsolvable?" There are many unsolvable problems in the world. Few of
them deserve to be posted to a beginners' discussion group.

I have a question about replacing $ sign when it is
before a digit.

It's done the same way as replacing a $ sign that isn't before a digit.

For example:

$str = "$1.12";

If you mean a real dollar sign, you have to backslash it. As you've
written that, it uses Perl's $1 variable. I assume you mean that $str
is the five-character string normally written in Perl as '$1.12'.

I want to extact the dollar amount 1.12 from $str.

You don't have to modify $str in order to do that.

my($dollar_amount) = ($str =~ /\$(\d+\.\d\d)/); # maybe?

If I do this:
$str =~ s/\$//;

$str then become .12.

Not if it had been '$1.12' before the substitution.

I can't use this:
$str ='$1.12' because the $1.12 is read from a file.

You seem to be under the impression that dollar signs in a data file
will be meaningful to Perl. No; data is data. Unless you're doing
something silly like using eval on a string, of course. Don't do that.

Hope this helps!

Phoenix
Stonehenge Perl Training

Xuning Wang schreef:

$str = "$1.12";

$str = '$1.12';

or

$str = q($1.12);

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

while (<DATA>)
{
print "$_\n" for /\$(\d+\.\d+)/g
}

__DATA__
Buy when the price goes from $1.12 to $0.98.
$12.345
$6
$7.8
$9.01