On Jan 26, 2008 1:13 PM, John Kufrovich <[EMAIL PROTECTED]> wrote:
> Chas,
> Thanks for the help. I'm not expert but I think your code will output each
> line.
snip
You don't have to be an expert to run the code and see what it does
(it only prints out the hour and temp for the first instance of each
hour). If you want to print out the whole line for the first instance
of each hour you can simplify the regex and the print:
#! /usr/bin/perl
use strict;
use warnings;
my %seen;
while (<DATA>) {
my ($hour) = / (..)/;
print unless $seen{$hour}++;
}
__DATA__
2007-01-23 00:01:00,43.3,34.9,30.14,North,359,7,8,72,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 00:06:00,43.2,34.8,30.14,North,354,11,11,72,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 00:12:00,43.2,34.8,30.14,North,1,6,9,72,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 01:11:00,42.9,34.8,30.13,North,1,5,6,73,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 01:17:00,42.9,34.8,30.12,NNW,346,3,7,73,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 01:23:00,43.1,35.0,30.12,North,359,5,11,73,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 02:14:00,43.2,34.1,30.10,North,0,16,16,70,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 02:19:00,43.2,34.1,30.09,North,0,6,13,70,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 02:24:00,43.2,33.7,30.09,North,349,8,14,69,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 03:04:00,43.2,34.1,30.11,North,0,7,12,70,0.00,,,0.00,Wunderground
v.1.13,
2007-01-23 03:09:00,43.2,34.1,30.11,North,0,10,17,70,0.00,,,0.00,Wunderground
v.1.13,
This can be further refined into a single command:
perl -ne '($h)=/ (..)/;print unless $s{$h}++' file_to_filter
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