So, I have an array of 2 types of events, and the times they occurred. I need to parse through the array and take teh time of the first Event A, and then find the first Event B after Event A, and calculate the time delta. using a simple grep on the array isn't a viable option because there could be multiple occurrences of Event A before there is an Event B, potentially looking like this:

EVENT A
EVENT A
EVENT B
EVENT A
EVENT A
EVENT A
EVENT B
EVENT A
EVENT B

I had initially thought of using a for loop with a dual index, something that would look kinda like this:

my $i = 0;
my $j = $i;
 
       for ( $i ; $i <= $#eventlist ; $i++ ){
          print "i is $i, j is $j\n";
          my ($subj,$date) = split(',',$eventlist[$i]);
          if ( $subj eq "Event B" ){
             while ( $subj ne "Event A" ){
                 $i++;
              ($subj,$date) = split(',',$eventlist[$i]);
             }
          print "i is $i, j is $j\n";
             $j = $i;
          print "i is $i, j is $j\n";
             my ($str,$date1) = split(',',$eventlist[$i]);
             my ($subj2,$x) = split(',',$eventlist[$j]);
             while ( $subj2 ne "Event B" ){
                 $j++;
             ($subj2,$x) = split(',',$eventlist[$j]);

[download]

But that never finished, and stayed at the top 2 events of the array. I was looking at the List::Util and List::MoreUtils modules, for the first adn first_idx functions, but I can't see how to update the list to have the function move from the last occurrence it returned of Event A or Event B. and I really can't do foreach because it just goes blindly through the entire list, and I want to be able to skip through the list after I find an event, to get to the corresponding second event.

Is there another iteration method I could be using, or a better set of list processing utilities? I have the Date::Manip module set up for teh date delta calculations, that was not hard. I just can't seem to get the list to process.

In reply to processing a list of events by BluePerlDev

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