Re: Using a Hash Variable in an If Statement

use warnings;
use strict;

my @names = qw(
    DONT
    MICH
    LEON
    RAPH
    SPLN
    SHRD
    CASY
    APRL
    FOOT
    BEBP
    RKST
    DUBY
    SAMH
    GRAW
    KNYN
    KP01
    KP02
    KP03
    KP04
    KP05
);

my %data;
while (<DATA>) {
    next if /mcp/;
    chomp;
    my ($s, $n) = split;
    push @{ $data{$s} }, $n;
}

my $i = 1;
for my $name (@names) {
    print "$i\n";
    print "$_\n" for @{ $data{$name} };
    $i++;
}

__DATA__
20131201.06372602.mcp
APRL 7.1963
BEBP 7.1979
CASY 7.3879
DONT 7.3196
DUBY 6.3729
FOOT 7.1496
GRAW 7.0046
KNYN 6.7313
LEON 7.4596
MICH 7.5579
RAPH 7.0563
RKST 6.6879
SAMH 6.9529
SHRD 6.2829
SPLN 6.1113
20131202.02185602.mcp
APRL -2.1870
BEBP -2.3270
CASY -1.0153
DONT -0.1453
DUBY -1.9920
FOOT -2.1903
GRAW -1.5937
KNYN -2.0403
LEON -0.6237
MICH -1.5737
RAPH -1.3287
RKST -2.5337
SAMH -1.9653
SHRD -2.4087
SPLN -2.2053
[download]

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Comment on Re: Using a Hash Variable in an If Statement Select or Download Code

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Re^2: Using a Hash Variable in an If Statement by Bama_Perl (Acolyte) on May 11, 2015 at 20:21 UTC
Could you possible explain the first while loop: `my %data; while (<DATA>) { next if /mcp/; chomp; my ($s, $n) = split; push @{ $data{$s} }, $n; }` [download] If my file I'm trying to read in is called rat_event, should I open it above, such as here: `open(rat_event,"RAT_EVENT"); @rat_event = <rat_event>;` [download] and then do: `my %rat_event; while <RAT_EVENT> { # Same as above }` [download] Thanks for the help.	[reply] [d/l] [select]
Re^3: Using a Hash Variable in an If Statement by edimusrex (Monk) on May 11, 2015 at 20:32 UTC
The first part is saying "check each line of the file (assigned to DATA, in your case rat_event) and if the line is equal to mcp, skip it (would skip 20131201.06372602.mcp and 20131202.02185602.mcp). Else chomp the line (remove new line and carriage return) and split the line into 2 variables (s and n, since no character is specified for the split it defaults to a space which would give you the station name and the time) and once it has those variables assigned it puts the values into the hash %data so s => 'n'. Yes you should load the file first as your code is shown `open my $fh, "<rat_event" or die "Failed to open:$!"; while(<$fh>) { #do something }` [download]	[reply] [d/l]
Re^4: Using a Hash Variable in an If Statement by Bama_Perl (Acolyte) on May 11, 2015 at 20:36 UTC
Thank you for the response, edimusrex. That makes a lot of sense now!	[reply]


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