Get a field from an Array of records - php

Question

How do I get all the values from a field in a record in an Array?
I want to make an average from a numerical score held under a specific field in an Array. The array is pulled from a form. Here is what I have so far but it just doesn't work.
$records = get_field('maths_month_report'); //gets all the records
$progressscore = $records['progress']; //targets the specific field in those records
echo . array_sum($progressscore)/count($progressscore) .; //divides the numbers in the field by the amount of records
revision: My apologies for not mentioning that the records are Arrays within the 'maths_month_report' Array. I can target specific fields in specific records with:
$firstrecord = $records[0];
$output = $firstrecord['progress'];
I just want to target all the 'progress' values so i can average them.

Answer 1

Based on your comments, if these are arrays within an array, you would need to build a new array:
$progresscore = array_column($records, 'progress')
PHP < 5.5:
$progresscore = array_map(function($item) {
return $item['progress'];
}, $records);
Or, just iterate yourself:
$sum = $count = 0;
foreach ($records as $record) {
$sum += $record['progress'];
++$count;
}
echo $sum / $count;