Re: subtractionn in an array

use strict;

my @List;

open(FILE, "filename.txt") or die "Unable to open file\n";

# assuming numbers, get them from file and add them to your array

while(<FILE>){
   #each time through the loop, line is held in $_
   chomp $_; #remove any newline from the line taken from file
   push(@List,$_); #push line into the array, in your case the number 
+you got
}   

close(FILE);

# to loop through the array, I found it usefull to increment my count 
+var ($i) by two
# here, scalar(@List), returns the number of elements in the array.

for(my $i=0;$i < scalar(@List);$i+=2){

   my $answer = ($List[$i+1]-$List[$i]); #use array indexing for your 
+calculation
   print "$answer\n";

}
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Re^2: subtractionn in an array by brachysclereid (Initiate) on Mar 21, 2012 at 17:57 UTC
Thanks for all the excellent information! I have learned more about array manipulation in the last hour than in the last day! I really appreciate the well annotated code! `#!/usr/bin/perl print "newbie thanks you all! \n"` [download] Cheers!, Art	[reply] [d/l]
Re^2: subtractionn in an array by Lotus1 (Vicar) on Mar 21, 2012 at 17:48 UTC
`# to loop through the array, I found it usefull to increment my count +var ($i) by two # here, scalar(@List), returns the number of elements in the array. for(my $i=0;$i < scalar(@List);$i+=2){` [download] Why increment by two?	[reply] [d/l]
Re^3: subtractionn in an array by Rudolf (Pilgrim) on Mar 21, 2012 at 23:30 UTC
Lotus1: can't remember why I did, hah, but maybe I misunderstood what he was trying to do.	[reply]