perl to get user input and print into file - arrays

Question

I am writing a perl script to get user input and add into text file. Multiple fruits and info are separated by coma. I wanted to achieve below req:
If the fruit provided in cmd line not exist in file, then add it in with the info provided. (jackfruit in below case)
If the fruit provided in cmd already exist in file, then add in info provided into it. Info 1 is mapping fruit1
Example cmd:
<scipt> -fruit apple,orange,jackfruit -info <info1>,<info2>,<info3>
Example of input file:
apple
x
y
orange
a
b
Expected output:
apple
<info1>
x
y
orange
<info2>
a
b
jackfruit
<info3>
My code:
use strict;
use warnings;
use Getopt::Long;
use Tie::File;
my $fruit;
my $info;
if (! GetOptions(
"fruit=s" => \$fruit,
"info=s" => \$info,
)){
print "\nEntered Arguments are not enough!\nPlease Use Switch '-help' or '-h' For More Information.\n";
exit;
}
my $split_info;
my $split_fruit;
my #split_info = split(',', $info);
my #split_fruit = split(',', $fruit);
tie my #file, 'Tie::File', 'filenamee.txt' or die $!;
for (0 .. $#file) {
if ($file[$_] eq "$split_fruit[0]") {
splice #file, $_ + 1, 0, "\t$split_info[0]\n";
}
}

Answer 1

Ok, so this works as far as it goes. But (as you've no doubt noticed) it only handles the first items in your inputs. And you want to handle all of them.
You could loop over #split_fruit for each line in your input and do clever stuff with #split_info when it matches, but I think it's easier to store both values in a hash (it also makes me slightly uncomfortable to have linked pieces of data stored in two separate data structures.
my %new_data;
#new_data{#split_fruit} = #split_info;
This is called a "hash slice" and it's an easy way to populate a hash when you have the keys and values in two separate arrays. It's really just a shortcut for:
for (0 .. $#split_fruit) {
$new_data{$split_fruit[$_]} = $split_info[$_]
}
We can now loop over our tied file array and easily check for the data we want to add.
for (0 .. $#file) {
# We can skip lines that start with whitespace
next if /^\s/;
# If our input is a key in the hash...
if (exists $new_data{$file[$_]}) {
# ... then add the value as a new line in the file
splice #file, $_ + 1, 0, "\t$new_data{$file[$_]}\n";
}
}
This gets us most of the way there. But it doesn't handle the case where we're adding new data to the file (your "jackfruit" example). So, here's what we're going to do:
As we process a record in the loop, we'll delete it from the hash
Once the loop has finished, if there are any keys left in the hash, then we know we have new data and we can run a new loop to add that.
So our code becomes something like this:
for (0 .. $#file) {
next if /^\s/;
if (exists $new_data{$file[$_]}) {
splice #file, $_ + 1, 0, "\t$new_data{$file[$_]}\n";
# Delete our current key/value pair from the hash
delete $new_data{$file[$_]};
}
}
# For each key left in the hash...
for (keys %new_data) {
# Push two new lines into our tied file array
# (This adds new lines to the end of the file)
push #file, "$_\n", "\t$new_data{$_}\n";
}