How to print data by avoiding last comma - arrays

Question

I have a data in my hash and trying to print them in the console.
Below is my script:
#!/usr/bin/perl
use strict; use warnings;
use Data::Dumper;
my %hash = (
'2022-08-04' => {
'Method 1' => {
'Count' => 50,
'Size' => '10 MB'
},
'Method 2' => {
'Count' => 40,
'Size' => '5 MB'
}
},
'2022-08-05' => {
'Method 1' => {
'Count' => 30,
'Size' => '3 MB'
},
'Method 2' => {
'Size' => '50 MB',
'Count' => '100'
}
}
);
my #headers = ("Method 1", "Method 2");
my #headers_data;
push (#headers_data, "Date");
foreach (#headers) {
push(#headers_data, $_." Size", $_." Count");
}
print join(",", #headers_data);
print "\n";
for my $date ( sort keys( %hash ) ) {
my $by_method = $hash{$date};
print "$date,";
for my $method ( #headers ) {
my $rec = $by_method->{$method};
$rec->{Size} = $rec->{Size} ? $rec->{Size} : "NA";
$rec->{Count} = $rec->{Count} ? $rec->{Count} : "NA";
print "$rec->{Size},$rec->{Count},";
}
print "\n";
}
Here when I print in line print "$rec->{Size},$rec->{Count},";, this gives , at the end of the result which looks odd to me.
Example:
Date,Method 1 Size,Method 1 Count,Method 2 Size,Method 2 Count
2022-08-04,10 MB,50,5 MB,40,
2022-08-05,3 MB,30,50 MB,100,
You can see there is a comma(,) in line 2 and 3 of the result.
When I tried below logic (which is similar of printing #headers_data) I got stuck how to proceed with printing #data in the console, since it contains two days data together.
...
my #data;
for my $date ( sort keys( %hash ) ) {
my $by_method = $hash{$date};
push (#data, $date);
for my $method ( #headers ) {
my $rec = $by_method->{$method};
$rec->{Size} = $rec->{Size} ? $rec->{Size} : "NA";
$rec->{Count} = $rec->{Count} ? $rec->{Count} : "NA";
push (#data, $rec->{Size}, $rec->{Count});
}
}
Could someone please help me to print results like below:
Date,Method 1 Size,Method 1 Count,Method 2 Size,Method 2 Count
2022-08-04,10 MB,50,5 MB,40
2022-08-05,3 MB,30,50 MB,100

Answer 1

Modifying your first script:
...
for my $date ( sort keys( %hash ) ) {
my $by_method = $hash{$date};
my #line_data;
push #line_data, $date;
for my $method ( #headers ) {
my $rec = $by_method->{$method};
$rec->{Size} = $rec->{Size} ? $rec->{Size} : "NA";
$rec->{Count} = $rec->{Count} ? $rec->{Count} : "NA";
push(#line_data, $rec->{Size}, $rec->{Count});
}
print join(",", #line_data), "\n";
}