How to convert a PHP array to a specific Javascript format

Question

I know this must be very basic but I really don't know how to solve this. I want to turn a php array to the following notation to be used inside a javascript script. These are countries which are passed to the js script in the initialization.

Source notation (PHP)

array(3) { [0]=> array(1) { ["code"]=> string(2) "AR" } [1]=> array(1) { ["code"]=> string(2) "CO" } [2]=> array(1) { ["code"]=> string(2) "BR" } }

Desired outcome (JS)

[ "AR", "FK","CO", "BO", "BR", "CL", "CR", "EC", "GT", "HN", "LT", "MX", "PA", "PY", "PE", "ZA", "UY", "VE"]

I can reformat the origin PHP array as desired, what I need to know is how to format it to get the desired outcome.

I am using the following code to pass the array to js:

echo "<script>var codes = " . json_encode($codes) . ";</script>";

Answer 1

Looks like the following would work for you:

<?php

$arr[0]['code'] = 'AR';
$arr[1]['code'] = 'CO';
$arr[2]['code'] = 'BR';

print_r($arr);


function extract_codes($var) { return $var['code']; }

print_r(array_map('extract_codes', $arr));

echo json_encode(array_map('extract_codes', $arr));

?>

Output:

Array
(
    [0] => Array
        (
            [code] => AR
        )

    [1] => Array
        (
            [code] => CO
        )

    [2] => Array
        (
            [code] => BR
        )

)
Array
(
    [0] => AR
    [1] => CO
    [2] => BR
)
["AR","CO","BR"]

It works by mapping each of the two-letter codes down to a normal one-dimensional array, then passing it to json_encode.

Answer 2

Going with array_reduce:

$output = array_reduce($array, function($result, $item){

    $result[] = $item['code'];
    return $result;

}, array());

echo json_encode($output);

Answer 3

You need to loop through your PHP associative array and set the appropriate variables. Like this:

$item = ''; // Prevent empty variable warning
foreach ($php_array as $key => $value){
  if (isset($key) && isset($value)) { // Check to see if the values are set
    if ($key == "code"){ $item .= "'".$value."',"; } // Set the correct variable & structure the items
  }
}
$output = substr($item,'',-1); // Remove the last character (comma)
$js_array = "[".$output."]"; // Embed the output in the js array
$code = $js_array; //The final product