Some might disagree with you regarding the clarity of the grep and map approach and a solution using loops of various flavours might be easier to maintain in the long run. However, here's a solution for you which wraps everything in a do block to contain the localization of paragraph mode.

use 5.022;
use warnings;

open my $logFH, q{<}, \ <<__EOD__ or die $!;
Message:
11 started at: 2018-06-29 16:20:07

Transmit: 
ATV1[0D]


Transmit: 
[01]10179311000=[03]

Receive: 
[01]20179321157>[02]00000068801400000000000000000000000000000000006880
+14000000
0000000068801400000000000000000000400000000040000000004000000000400000
+00000000
000000000000000000[03][00]

Transmit: 
[01]10179312000>[03]

Receive: 
[01]20179331157?[02]00000068801400000000000000000000000000000000006880
+14000000
0000000068801400000000000000000000400000000040000000004000000000400000
+00000000
000000000000000000[03][00]

Transmit: 
[01]10179313000?[03]

Receive: 
[01]201793411578[02]00000068801400000000000000000000000000000000006880
+14000000
0000000068801400000000000000000000400000000040000000004000000000400000
+00000000
000000000000000000[03][00]

Transmit: 
[01]101793140008[03]

Receive: 
[01]201793511579[02]00000068801400000000000000000000000000000000006880
+14000000
0000000068801400000000000000000000400000000040000000004000000000400000
+00000000
000000000000000000[03][00]

Transmit: 
[01]101793150009[03]

Receive: 
[01]001793611578[02]00000068801400000000000000000000000000000000006880
+14000000
0000000068801400000000000000000000400000000040000000004000000000400000
+00000000
000000000000000000[03][00]



Message:
reading of spontaneous buffer not ordered

Message:
Periodic Buffer: Start: 2018-06-29 13:15:00 End: 2018-06-29 16:10:00
Periods: 36  Dec: 8  Points: 15  bytes collected: 5564  estimated: 556
+4

Message:
amount of bytes collected ok, data accepted 

Message:
11 ended at: 2018-06-29 16:20:46
__EOD__

my @records = do {
    local $/ = q{};
    map  {
        join q{ },
           map {
               m{\[\d\d\]}
               ? substr $_, 1, 2
               : map { sprintf q{%02x}, ord } split m{};
           } @$_;
    }
    map  {
        s{^Receive:}{};
        s{\s+}{}g;
        [ split m{(\[\d\d\])} ];
    }
    grep { m{^Receive:} }
    <$logFH>;
    };

say qq{$_\n} for @records;

[download]

I don't show the output here as it will wrap horribly. Despite giving you this solution I would recommend sticking with looping constructs.

Update: Got rid of the middle map by moving the split into the first map.

Update 2: The first update would have made more sense if I'd included the original code so here it is :-

    map  {
        join q{ },
           map {
               m{\[\d\d\]}
               ? substr $_, 1, 2
               : map { sprintf q{%02x}, ord } split m{};
           } @$_;
    }
    map  { [ split m{(\[\d\d\])} ] }
    map  {
        s{^Receive:}{};
        s{\s+}{}g;
        $_;
    }
    grep { m{^Receive:} }
    <$logFH>;

[download]

Cheers,

JohnGG

In reply to Re: how use map and grep or several loops? by johngg
in thread how use map and grep or several loops? by Anonymous Monk

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