gi|12345678|ref|NP_001234.1|

##</code><code>##

$data = gi|12345678|ref|NP_001234.1|;
@data = split ('gi|',$data);
@data1 = split ('|ref',$data[1]);
$number = $data1[0];


##</code><code>##

$data = gi|12345678|ref|NP_001234.1|;
@data = split ('gi',$data);
@data1 = split ('ref',$data[1]);
$number = $data1[0];

##</code><code>##

$number =~ m/[0-9]*/;