How to dynamically set array keys in php

Question

I have some logic that is being used to sort data but depending on the user input the data is grouped differently. Right now I have five different functions that contain the sa

Answer 1

I agree with the comment on the OP by @Jake N that perhaps using objects is a better approach. Nonetheless, if you want to use arrays, you can check for the existence of keys in a conditional, like so:

if(
    array_key_exists('Resource', $meter)
) {
    $calcs[$meter['Resource']['name']][$meter['UnitType']['name']][date('Y-m',$start)] = $data;
} else {
    $calcs[$meter['UnitType']['name']] = $data;
}

On the other hand, if you want to use objects, you can create a MeterReading object type, and then add MeterReading instances as array elements to your $calcs array, like so:

// Object defintion
class MeterReading {
    private $data;
    private $resource;
    private $startDate;
    private $unitType;

    public function __construct(Array $meter, $start, $data) {
        $this->unitType   = $meter['UnitType']['name'];
        $this->resource   = $meter['Resource']['name'];
        $this->startDate  = date('Y-m',$start);
    }

    public function data() {
        return $this->data;
    }

    public function resource() {
        return $this->resource;
    }

    public function startDate() {
        return $this->startDate;
    }

    public function unitType() {
        return $this->unitType;
    }
}

// Example population
$calcs[] = new MeterReading($meter, $start, $data);

// Example usage
foreach($calcs as $calc) {
    if($calc->resource()) {
        echo 'Resource: ' . $calc->resource() . '
';
    }
    echo 'Unit Type: ' . $calc->unitType() . '
';
    echo 'Start Date: ' . $calc->startDate() . '
';
    echo 'Data: ' . $calc->data() . '
';
}

Obviously you can take this further, such as checking the existence of array keys in the object constructor, giving the object property resource a default value if not provided, and so on, but this is a start to an OO approach.