parse problem

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

I want to get the number from a html source file, I want to parse the data like:

gi|12345678|ref|NP_001234.1|
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and get 12345678, I did as below:

$data = gi|12345678|ref|NP_001234.1|;
@data = split ('gi|',$data);
@data1 = split ('|ref',$data[1]);
$number = $data1[0];
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I got e, g,..., some weird letter, when I changed the code to below:

$data = gi|12345678|ref|NP_001234.1|;
@data = split ('gi',$data);
@data1 = split ('ref',$data[1]);
$number = $data1[0];
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I got:|12345678|, I try use regular expression to remove the |:

$number =~ m/[0-9]*/;
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I got the same thing which has |12345678|, What can I do? Please help and Thanks in advance! Please help and Thanks in advance!

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Re: parse problem by DrManhattan (Chaplain) on Apr 20, 2003 at 02:05 UTC
The first argument to split() needs to be a regular expression matching the string that delimits the fields in your data. In your case, the fields in your line are separated by a '\|', so the code could look like this: `#!/usr/bin/perl use strict; my $data = 'gi\|12345678\|ref\|NP_001234.1\|'; my @data = split /\\|/, $data; my $number = $data[1];` [download] Or more concisely: `#!/usr/bin/perl use strict; my $data = 'gi\|12345678\|ref\|NP_001234.1\|'; my $number = (split(/\\|/, $data))[1];` [download] -Matt	[reply] [d/l] [select]
Re: parse problem by dpuu (Chaplain) on Apr 20, 2003 at 01:46 UTC
Your problem may be that the first arg to split is a regular extression -- and the vertical bar is a pattern separator with an empty extression on its left -- which can always match. If you are only wanting the one number you show, then your could use: `$data =~ /gi\\|(\d+)\\|ref/ and $number = $1;` [download] Note that the vertical bar is escaped using the backslash. --Dave	[reply] [d/l]
Re: parse problem by artist (Parson) on Apr 20, 2003 at 04:50 UTC
Hi You have already received good solutions. Your algorithm should be: A. split the data with the pattern . (pipe symbol in your case) B. get the second item from the result of the above split. Learn more about split. artist	[reply]