Add to (not overwrite) a global variable from a Loop PHP - php

Question

I'm working on a php script that adds up points from voting using the borda count. I've got files read, data set up, but I'm struggling to set up a way to put an individuals points into their array. Right now I have an array of candidates, and an array of votes. I'm attempting to add up the votes and put them inside of the candidate array. The first number in each vote index responds to the first candidate, and so on. I have the program calculating the vote points correctly, but I can't get them to add together so I have the final number once it finishes.
edit: This script is also supposed to be scalable, meaning if I have 6 candidates, rather than 4, it will work. If there's something that jumps out at the reader saying it won't work, please let me know
<?php
$file = $argv[1];
$inputFile = fopen($file,"r");
$candidates = fgets($inputFile);
$candidates = str_replace(' ','',$candidates);
echo $candidates;
$candidates = explode(',',$candidates);
print_r($candidates);
$numCandidates = count($candidates);
echo "The number of candidates is: " . $numCandidates. "\n";
/**
$testFile = file_get_contents("$argv[1]");
$testFile = explode('\n',$testFile);
print_r($testFile);
*/
while (!feof($inputFile)){
$votes[] = trim(fgets($inputFile),"\n");
}
unset($votes[count($votes)-1]);
//$votes = trim("\n",$votes);
//$votes = explode(',',$votes);
print_r($votes);
for ($i = 0; $i<count($votes); $i++){
$votes[$i] = str_replace(',','',$votes[$i]);
}
print_r($votes);
/**
for($x = 0;$x<count($candidates);$x++){
$z = 0;
for($y = 0;$y<count($votes);$y++){
$candidates[$x][$y] = $votes[$y][$z];
}
print_r($candidates[0]);
$z++;
}
*/
for ($x = 0; $x<count($votes);$x++){
global $candidates;
for ($y=0; $y<count($candidates);$y++){
$candidates[$y][0]= (($numCandidates + 1)-$votes[$x][$y]);
echo "\nThe value of candidate $y is " . $candidates[$y][0];
}
}
?>
This is where I'm attempting to add to the amount, but it just keeps overwriting.
for ($x = 0; $x<count($votes);$x++){
global $candidates;
for ($y=0; $y<count($candidates);$y++){
$candidates[$y][0]= (($numCandidates + 1)-$votes[$x][$y]);
echo "\nThe value of candidate $y is " . $candidates[$y][0];
}
}
Edit: When I attempt to use += rather than = in
$candidates[$y][0] = (($numCandidates + 1)-$votes[$x][$y]);
I get an error saying "can't use assign-op operators with overloaded objects nor string offsets"

Answer 1

$candidates[$y][0] = (($numCandidates + 1)-$votes[$x][$y]);
That = should be += so that your loop keeps adding the value, instead of overwriting the existing value on every iteration.
$candidates[$y][0] += (($numCandidates + 1)-$votes[$x][$y]);