A simple grouping of list items

[Lady_Aleena]

I wanted to group some list items when I went to print it out so I could insert sleep between the groups. This little thing is what I came up with. I know it is not big and complex, but I was pretty happy with it. (I recently rewrote the script this was in and do not need it anymore, so I decided to share it here.)

my $previous = "";
for my $item (@list) {
  sleep(5) if $item !~ /^$previous/;
  print $item;
  $previous = $item;
  $previous =~ s/^(.+)\: .+/$1/; # the regex by which you want to grou
+p your items
}

Update: The regex currently in the code is what I was using, you can use whatever regex fits your need.

[monsoon]

Just for fun, golfing...

"" =~ /()/;
for (@list) {
  sleep(5) if !/^$1/;
  print;
  /^(.+)\:/;
}

By the way the original script wasn't working if the items were ending with \n, because \n wasn't being replaced and $item was never matching $previous on the next iteration. However, if there were no \n characters, I had to set $| to non zero to get the expected behavior, otherwise output was getting buffered and was printed in one chunk at the very end.

[ruzam]

What the heck, just for fun, some minor code changes for faster execution.

caveat: not tested, not benchmarked, maybe not even syntactically correct, could cause different output :)

my $previous = "";

# skip $item variable
# 'for' just looks funny in this use
foreach (@list) {
  # regex once instead of twice 
  # no extra work shuffling $previous back and forth until needed
  if (m/^(.+)\: .+/ and $1 ne $previous) {
     $previous = $1;

     # take the sleep hit on the first item to save time later
     # (maybe even 5 seconds worth if you have a lot of items)
     sleep(5);
  }
  print $_;
}