perl loop to add element from last line to new line.

[Natalie30]

my $data_file = "/root/bin/load.data2";
open(FILE,&quot;<$data_file&quot or die &quot;Cant open $data_file2: $!\n&quot;;
my @log = <FILE>;
close(FILE);
my $last_element='&quot;0&quot;';
while (<>){
chomp;
@log = split ',';
print &quot;$_, $last_element\n&quot;;
$last_element = $log[$#log];
}

just need a little help with this, not sure if my code is going in the right direction.
thanks.
Nat

 

[rosenk]

Ah, not quite. The [tt]while (<>)[/tt] is reading lines from standard input. You've already read lines from [tt]FILE[/tt].

You can change the script to:
[tt]my $data_file = &quot;/root/bin/load.data2&quot;;
open(FILE,&quot;<$data_file&quot or die &quot;Cant open $data_file2: $!\n&quot;;
my $last_element='&quot;0&quot;';
while (<FILE>){
chomp;
my @log = split ',';
print &quot;$_, $last_element\n&quot;;
$last_element = $log[$#log];
}
close(FILE);[/tt]

There's no real need to read the entire file in first before processing it in this case. If you really wanted to do that, you could keep your code as is, but change
[tt]while (<>) {
chomp;
@log = split ',';
print &quot;$_, $last_element\n&quot;;
$last_element = $log[$#log];
}[/tt]

to:
[tt]foreach (@log) {
chomp;
my @list = split ',';
print &quot;$_, $last_element\n&quot;;
$last_element = $list[$#list];
}[/tt]

[tt]foreach[/tt] will do the block for each element in the array, setting [tt]$_[/tt] to the element each time.

Note that the block itself now uses [tt]@list[/tt] inteaed of [tt]@log[/tt] for the split elements. Using [tt]@log[/tt] as you were got rid of the text of the file you'd read into that same list.