Hey dude, not everywhere has perfect climate like Santa Monica! As you may know, negative temps exist at some locations (and are denoted with a leading 'M' in METAR reports).

Here is the skeleton of a solution handling negative temperatures (using the reading from Fairbanks, AK at this time for testing).

(But see also Geo::METAR for an oldie-but-goodie parser for this format, which provides the temp in F in its dump output.) 

use strict;
use warnings;

while ( my $line = <DATA> ) {
    $line =~ s{ \s (M?\d{2}) / (M?\d{2}) \s }
              { sprintf ' %d/%d ', convert($1), convert($2) }xeg;
    print $line;
}

sub convert { $_[0] =~ s/M/-/r * 9/5 + 32 };

__DATA__
KSMO 181551Z 00000KT 10SM CLR 14/08 A3009 RMK AO2 SLP189 T01440083
PAFA 190153Z 00000KT 5SM -SN BR FEW012 BKN025 OVC070 M07/M08 A2959 RMK
+ AO2 SLP030 T10671078

[download]
Output: 
KSMO 181551Z 00000KT 10SM CLR 57/46 A3009 RMK AO2 SLP189 T01440083
PAFA 190153Z 00000KT 5SM -SN BR FEW012 BKN025 OVC070 19/17 A2959 RMK A
+O2 SLP030 T10671078

[download]

Hope this helps!


The way forward always starts with a minimal test.

In reply to Re: substitution with regex by 1nickt
in thread substitution with regex by drose2211

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