UNIX for Dummies Questions & Answers

Assuming that there are different values in the first field (SK1.chr15), you can try this:

Code:

#!/usr/bin/perl
open I, "$ARGV[0]";
local $/;
$_=<I>;
$x=1;
while (/(.*)\n(\d+)-(\d+)\nRef:\n.*\n\nGen:\n(.*)/g){
  $h{$1}.="N" x ($2-$x) . $4;
  $x=$3+1;
}
for $i (keys %h){
  print "$i\n";
  print "$h{$i}\n";
}

That was really short, quick and efficient ... thank you ... could you please explain how it does the job, escpecially the use of $/ and $_ variables? The rest is pretty clear to me .. The four numerical variables store the regex matches in the while loop if I'm right ?? and the .= is short for concatenation ?
Cheers Bartus

Yes, that is right what you said about $1,$2.. and .=. Unsetting $/ variable results in whole file being loaded into variable as single string (into $_ in this case). $_ is the default variable for many Perl's operators, for example if you use "print" function like this:

Code:

print;

it is equivalent to:

Code:

print $_;

In this code $_ is used as the regex target for regular expression in while's condition part (so the matching is performed on file's contents). It is equivalent to this:

Code:

while ($_=~/(.*)\n(\d+)-(\d+)\nRef:\n.*\n\nGen:\n(.*)/g){

So $/ can store whole files as single strings ... thanks for that tip ... does this mean it performs chomp and removes newline characters automatically from the input file while being fed into $_?
Thanks for your input and comments
Cheers ++

No, $/ is only a record separator variable, that is not connected to chomp (removing last newline).

Congratulations! Great (if nail-biting) match.

This thread has deviated so much from the original question, and wil soon have more posts than India got runs!

If you have a new question please start a new thread.

Thank you.

Closed.

Hi All,
I want to make some changes in a code here https://www.unix.com/302508078-post55.html
So basically I want to input a coverage value of choice and report the results of the above code only for the lines which have coverage value equal to or greater than those input by user (me). What could be changed in the code to achieve this? Can someone enlighten on this?
Thanks for your input
Hv a nice day
Cheers