Insert Element Into Array

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

How do I insert a line of text into an existing array?

 #!/usr/bin/perl

use strict;
use warnings;

my @data;
my $line;
my %hashTemp;

open(FH, "error_log");
@data = <FH>;

foreach $line (@data) {
    if ($line =~ /notice/) {
        if ($line =~ /rdy/) {
            $line =~ s/ /,/g;    
            my @L1 = split(/|notice|[[]|,mpmstats:,|[\t]|rdy,|bsy,|rd,
+|wr,|ka,|log,|dns,|cls,/, $line);    
            %hashTemp = map { $_ => 1 } @L1;
            print @L1;
                }
            }
        }
[download]

I would like the following to go on the first line in the array:

day, month, date, time, year, rdy, bsy, rd, wr, ka, log, dns, cls

The output currently looks like this:

 
Wed,Jun,13,10:42:35,2012,769,31,0,22,6,0,0,3
[download]

Comment on Insert Element Into Array Select or Download Code

Replies are listed 'Best First'.
Re: Insert Element Into Array by frozenwithjoy (Priest) on Jun 21, 2012 at 05:51 UTC
You can use splice. Here is an example: `use Modern::Perl; my @nums = qw( 1 2 3 4 5 6 ); say @nums; splice( @nums, 3, 0, "combo breaker" ); say @nums;` [download] Output: `123456 123combo breaker456` [download]	[reply] [d/l] [select]
Re: Insert Element Into Array by NetWallah (Canon) on Jun 21, 2012 at 05:47 UTC
Which array would you like to insert it into ? Why ? Wouldn't it be easier to just print "day, month, date, time, year, rdy, bsy, rd, wr, ka, log, dns, cls\n" first before processing ? The 'unshift' function is useful in pre-pending an element to an array. I hope life isn't a big joke, because I don't get it. -SNL	[reply]
Re^2: Insert Element Into Array by Anonymous Monk on Jun 21, 2012 at 15:30 UTC
I would like to insert it in @L1 on the first line. I can't print the string because it needs to eventually be output as a CSV file. If I were to print it within the loop it would print on every other line. I still haven't found a simple solution to this. Any ideas?	[reply]
Re^3: Insert Element Into Array by NetWallah (Canon) on Jun 21, 2012 at 22:13 UTC
But you are re-initializing @L1 (You use my @L1) inside the "for $line" loop. So, anything you add at the beginning will be obliterated by the re-initialization. Please re-think your logic, and reconsider my suggestion to print the titles first, before entering the loop. It matters little that the "print" output is redirected to a CSV file. I hope life isn't a big joke, because I don't get it. -SNL	[reply]
Re: Insert Element Into Array by roboticus (Chancellor) on Jun 21, 2012 at 11:05 UTC
There are many ways you can insert data into an array: `push` and `unshift` let you easily insert at the ends. You can also insert at the ends with simple assignment: `@T = ( 'FIRST', @T, 'LAST' );` You can also use the aforementioned `splice` to insert items in the middle of a list. Reassigning with slices can also do the trick: `@T = (@T[0..50], 'FOO', 'BAR', @T[51..$#T]);` I frequently find myself rebuilding lists into new lists as I process items: `my @tmp; for my $item (@T) { if (..insert condition..) { push @tmp, 'Scooby Doo!'; } if (..keep condition..) { push @tmp, $item; } } @T = @tmp;` [download] Which method(s) you choose depend on which is most convenient in the code you're writing. Notes: None of these have been tested, and the ...blah.. need to be replaced with appropriate expressions. ...roboticus When your only tool is a hamster, all problems are short-lived. R.I.P. Hammy ~1970 .. 1972	[reply] [d/l] [select]
Re: Insert Element Into Array by cheekuperl (Monk) on Jun 21, 2012 at 05:42 UTC
Related to this? Btw, you could `split $line` on comma and use the required fields.	[reply] [d/l]