Splitting one txt file into multiple txt files based on delimiter and naming them with a specific character - perl

Question

I have a text file that looks like this http://www.uniprot.org/uniprot/?sort=score&desc=&compress=no&query=id:P01375%20OR%20id:P04626%20OR%20id:P08238%20OR%20id:P06213&format=txt.
This file is contained of different entries that are divided with //. I think I have almost found the way how to divide txt file into multiple txt files whenever this specific pattern appears, but I still don't know how to name them after dividing and how to print them in specific directory. I would like that each file that is divided carries specific ID which is a first line nut second column in each entry.
This is the code that I have wrote so far:
mkdir "spliced_files"; #directory where I would like to put all my splitted files
$/="//\n"; # divide them whenever //appears and new line after this
open (IDS, 'example.txt') or die "Cannot open"; #example.txt is an input file
my #ids = <IDS>;
close IDS;
my $entry = 25444; #number of entries or //\n characters
my $i=0;
while ($i eq $entry) {
print $ids[$i];
};
$i++;
I am still having problem with finding how to split all entries from 'example.txt' file whenever "//\n" and to print all this seperated files into directory spliced_files. In addition I would have to name all of these seperated files with the ID that is specific for each of these files or entries (which appears in the first row, but only a second column).
So I expect output to be number of files in spliced_files directory, and each of them are named with their ID (first row, but only second column). For example name of the first file wiould be TNFA_HUMAN, od the second would be ERBB2_HUMAN and so on..)

Answer 1

You still look like you're programming by guesswork. And you haven't made use of any of the advice you have been given in answers to your previous questions. I strongly recommend that you spend a week working through a good beginners book like Learning Perl and come back when you understand more about how Perl works.
But here are some comments on your new code:
open (IDS, 'example.txt') or die "Cannot open";
You have been told that using lexical variables and the three-arg version of open() is a better approach here. You should also include $! in your error message, so you know what has gone wrong.
open my $ids_fh, '<', 'example.txt'
or die "Cannot open: $!";
Then later on (I added the indentation in the while loop to make things clearer)...
my $i=0;
while ($i eq $entry) {
print $ids[$i];
};
$i++;
The first time you enter this loop, $i is 1 and $entry is 25444. You compare them (as strings! You probably want ==, not eq) to see if they are equal. Clearly they are different, so your while loop exits. Once the loop exits, you increment $i.
This code bears no relation at all to the description of your problem. I'm not going to give you the answer, but here is the structure of what you need to do:
mkdir "spliced_files";
local $/ = "//\n"; # Always localise changes to special vars
open my $ids_fh, '<', 'example.txt'
or die "Cannot open: $!";
# No need to read the whole file in one go.
# Process it a line at a time.
while (<$ids_fh>) {
# Your record (the whole thing, not just the first line) is in $_.
# You need to extract the ID value from that string. Let's assume
# you've stored in it $id
# Open a file with the right name
open my $out_fh, '>', "spliced_files/$id" or die $!;
# Print the record to the new file.
print $out_fh $_;
}
But really, you need to take the time to learn about programming before you attack this task. Or, if you don't have the time for that, pay a programmer to do it for you.