Re^2: Using a Hash Variable in an If Statement

Could you possible explain the first while loop:

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

my %rat_event;
while <RAT_EVENT> {
# Same as above
}
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Thanks for the help.

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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]