Regex problem

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

Hello
I download a web page that includes data used and remaining data for a mobile connection.
I want to find the two values and convert them from strings to values.

A snippet of the html page is:

<span class="remaining-data">54MB used</span>
<span class="expires-data-right-align">1.44GB remaining</span>
[download]

I use the regex to get a matching substring with the 1st value within

  (my $DataUsed) = $stgUsed =~ /"remaining-data">([+-]?(\d*\.)?\d+)(MB
+|GB) used/;  # trying to get just the digits.
  (my $unit) = $stgUsed =~ /(MB|GB)/;  # match either MB or GB
  if ( $unit eq "GB"){  $DataUsed *= 1000; }
[download]

The output in $stgUsed is what I expect:

  DB<5> x $stgUsed
0  'class="remaining-data">315MB'
[download]

In want to capture just the number (315) and the units (MB) but $DataUsed in undef.
I have tried using $1,$2 ... but they are undef as well.

How to I get the digits substring and the MB/GB substring????

Dazz

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Re: Regex problem by haukex (Archbishop) on May 25, 2017 at 09:49 UTC
You will be doing yourself a huge favor if you use a module to parse HTML instead of regexes. I discussed some of the options for parsing HTML and gave some example code here: "Two classic modules are HTML::Parser and HTML::TreeBuilder, but there are several others, such as Mojo::DOM. If the input is always XHTML, there's XML::Twig and many more XML-based modules." `use warnings; use strict; use Data::Dump; use Mojo::DOM; my $html = <<'END_HTML'; <span class="remaining-data">54MB used</span> <span class="expires-data-right-align">1.44GB remaining</span> END_HTML my $dom = Mojo::DOM->new($html); for my $e ($dom->find('span[class="remaining-data"]')->each) { dd $e->text; my ($val,$unit) = $e->text =~ /([+-]?(?:\d*\.)?\d+)(MB\|GB) used/ or die "Couldn't parse '".$e->text."'"; dd $val, $unit; } __END__ "54MB used" (54, "MB")` [download]	[reply] [d/l]
Re: Regex problem by Corion (Patriarch) on May 25, 2017 at 09:42 UTC
I would restructure the code to be less clever but easier to debug: `if( $html !~ m!<span class="remaining-data">\s(.?)used\s*</span>! ) +{ die "Couldn't find 'remaining-data' span in html!"; }; my $remaining = $1; if( $remaining !~ m!^(\d+(?:\.\d+))(MB\|GB)$! ) { die "Weirdo string instead of remaining data: [$remaining]"; }; my ($DataUsed, $unit) = ($1,$2);` [download]	[reply] [d/l]