How to clear $1 's values ?

[sonet]

===========================================================================
use strict;
my $a;
my $from;
my $to;
my $id;
my $node;
$a="<info id='id1' to='test\@se6.program.com.tw' type='get'
from='luke\@se6.program.com.tw'/>";

$a =~/ from\=['|"](.*?)['|"][ |>|\/>]/;
$from=$1;
$a =~/ id\=['|"](.*?)['|"][ |>|\/>]/;
$id=$1;
$a =~/ node\=['|"](.*?)['|"][ |>|\/>]/;
$node=$1;

print $node;

 

[Graham Wood]

===========================================================================
use strict;
my $a;
my $from;
my $to;
my $id;
my $node;
$a="<info id='id1' to='test\@se6.program.com.tw' type='get'
from='luke\@se6.program.com.tw'/>";

$a =~/ from\=['|"](.*?)['|"][ |>|\/>]/;
$from=$1;
$a =~/ id\=['|"](.*?)['|"][ |>|\/>]/;
$id=$1;
$a =~/ node\=['|"](.*?)['|"][ |>|\/>]/;
$node=$1;

print $node;

I'm assuming that your problem is that $node gets set to the id value
because there is nothing matched for the node. I'd suggest using an if
statement before assigning $1.

if($a =~/ node\=['|"](.*?)['|"][ |>|\/>]/){
$node = $1;
}

Graham

 

[Brian McCauley]

$a =~/ node\=['|"](.*?)['|"][ |>|\/>]/;
$node=$1;

I'd suggest using an if statement before assigning $1.

if($a =~/ node\=['|"](.*?)['|"][ |>|\/>]/){
$node = $1;
}

Or, a better idiom IMNSO...

my ($node) = $a =~/ node\=['|"](.*?)['|"][ |>|\/>]/;

 

[Mark Clements]

===========================================================================
use strict;
my $a;
my $from;
my $to;
my $id;
my $node;
$a="<info id='id1' to='test\@se6.program.com.tw' type='get'
from='luke\@se6.program.com.tw'/>";

$a =~/ from\=['|"](.*?)['|"][ |>|\/>]/;
$from=$1;
$a =~/ id\=['|"](.*?)['|"][ |>|\/>]/;
$id=$1;
$a =~/ node\=['|"](.*?)['|"][ |>|\/>]/;
$node=$1;

print $node;

Just a thought (this doesn't answer your question):

If you are trying to parse XML, you are better off using a parser.

XML::Simple may be adequate for your needs, if not try XML::LibXML or
similar.

regards,

Mark

 

[Damian James]

if($a =~/ node\=['|"](.*?)['|"][ |>|\/>]/){
$node = $1;
}

Or, a better idiom IMNSO...

^
You're dropping your aitches .

my ($node) = $a =~/ node\=['|"](.*?)['|"][ |>|\/>]/;

or indeed:

my $node = ($a =~ / node\=['|"](.*?)['|"][ |>|\/>]/)[0];

--Damian

 

[Joe Smith]

Question: How to clear $1 's values ?

Answer: Don't use $1 when the previous regex did not match.
Use 'if(){}' or 'and' to avoid the non-matches.

$a =~/ from\=['|"](.*?)['|"][ |>|\/>]/;
$from=$1;
$a =~/ id\=['|"](.*?)['|"][ |>|\/>]/;
$id=$1;
$a =~/ node\=['|"](.*?)['|"][ |>|\/>]/;
$node=$1;

$a =~/ from=['|"](.*?)['|"][ |>|\/>]/ and $from=$1;
$a =~/ id=['|"](.*?)['|"][ |>|\/>]/ and $id=$1;
$a =~/ node=['|"](.*?)['|"][ |>|\/>]/ and $node=$1;

-Joe