REGexp match query

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

I am trying to match this output.

Queue counters:  Queued packets  Trans packets   Dropped pak
    0            258520344       520344                    0
    1            11006822       1006822                    0
    2            832114        0832114                    0
    3            8294677        8294677                    0
    4            5416057        5416057                    0
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I want to check , whether Queue counters: is 0 and there are digits for both Queued packets and Trans packets and Dropped Pak is 0. Similarly for other Queue counters till 4


                $rh->cmd('show class-of-service interface et-0/3/0 com
+prehensive | find " Queue counters:"');--> this displays the above ou
+tput, internal command
                my $output = $rh->get_response;
                my @outputlist = split /\n+/, $output;
                foreach (0..$#outputlist) {
                        if (($outputlist[$_] = /^0/) && ($outputlist[$
+_] = /^0\s(\d+)\s(\d+)/))  {
                            print " match is $outputlist[$_]\n";
                        }
                }
    }
[download]

In the above code for sample, i tried to match Q 0 and space and then digit for the Queued packets & Trans packets respectively. Looks to me its not matching. anything missing here

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Re: REGexp match query
by toolic (Bishop) on Oct 09, 2015 at 13:33 UTC

$outputlist[$_] = /^0/
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=~

It might be easier to use split:

use warnings;
use strict;

while (<DATA>) {
    chomp;
    if (s/^\s+//) {
        my @cols = split;
    }
}

__DATA__
Queue counters:  Queued packets  Trans packets   Dropped pak
    0            258520344       520344                    0
    1            11006822       1006822                    0
    2            832114        0832114                    0
    3            8294677        8294677                    0
    4            5416057        5416057                    0
[download]

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Re^2: REGexp match query

by karlgoethebier (Abbot) on Oct 09, 2015 at 14:42 UTC

"... easier to use split..."

Yes. Perhaps even more simplified?

<DATA>;

while (<DATA>) {
    chomp;
    my @cols = split;
}
[download]

Regards, Karl

ŤThe Crux of the Biscuit is the Apostropheť

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Re: REGexp match query
by Athanasius (Archbishop) on Oct 09, 2015 at 14:03 UTC

A few additional observations:

In the foreach loop there is no need for explicit indices, since these are used only to identify array elements. It’s simpler and clearer to loop directly over the elements themselves: for (@outputlist) { This has the additional benefit that you don’t need to use the binding operator (=~) explicitly, because $_ is “understood”:
```
for (@outputlist) {
    print ... if /.../;
}
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```
Testing that a string matches /^0/ and then testing that it matches a longer pattern beginnning with /^0.../ is fairly pointless here.
The input line:
```
"    0            258520344       520344                    0"
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```
will not match any pattern beginning /^0.../ because there is whitespace before the zero digit. You need something like this:
```
/ ^ \s* 0 \s+ (\d+) \s+ (\d+) \s+ 0 \s $ /x
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```
Note the quantifiers: * means zero or more, + means one or more. See “Quantifiers” in perlre. (The /x modifier just makes the regex easier to read.)

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

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Re: REGexp match query
by hippo (Archbishop) on Oct 09, 2015 at 13:32 UTC

if (($outputlist[$_] = /^0/) && ($outputlist[$_] = /^0\s(\d+)\s(\d+)/)) {

That line contains assignments (the = operator) rather than matches (the =~ operator). Try using the latter and see how much closer you get to your desired functionality. See also perlop for more on operators.

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Re^2: REGexp match query

by Anonymous Monk on Oct 09, 2015 at 13:53 UTC

That doesn't help either

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Re^3: REGexp match query

by Laurent_R (Canon) on Oct 09, 2015 at 15:42 UTC

Update: corrected a typo (s/\sup\s/\sus\s/).

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Re: REGexp match query
by RichardK (Parson) on Oct 09, 2015 at 15:11 UTC

Split just isn't going to work if you can have missing columns. If split returns 3 columns how are you going to guess which one is missing?.

The data you posted looks like it's a fixed length format, so you'd be better using unpack

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Re: REGexp match query
by flexvault (Monsignor) on Oct 09, 2015 at 15:42 UTC

Dear Monks,

I would use the following to get at the data in each line: (untested)

   my $output = $rh->get_response;
      $output = join( " ", split " ", $output );
      my @outputlist = split /\ /, $output;
      foreach (0..$#outputlist)
      {
          . . .
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Regards...Ed

"Well done is better than well said." - Benjamin Franklin

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