#!/usr/bin/perl
use strict;
use warnings;
use 5.014;

# desired: name=John&number=7&status=unknown 

my @arr = qw(name John number 7 status unknown);
my $i = 0;
my $str = "$arr[$i]=$arr[++$i]";
$str .= "&$arr[++$i]=$arr[++$i]";
$str .= "&" . "$arr[++$i]=$arr[++$i]";
say $str;