带有嵌套数组的PHP create_function

Question

I need to use create_function because the server the application is running on has an outdated version of PHP.

The issue is that the items I pass into usort are arrays and I need to sort by a value within the array:

$sort_dist = create_function( '$a, $b', "
    if( $a['order-dir'] == 'asc' ) {
        return $a['distance'] > $b['distance'];
    }
    else {
        return $a['distance'] < $b['distance'];
    }" 
);

usort( $items, $sort_dist );

Gives an error: syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING

Removing the references to ['distance'] and ['order-dir'] removes this error.

Does anyone know how to use create_function with nested arrays?

Answer 1

Don't use create_function in this instance. You can also write it like this:

function sort_by_distance($a, $b) {
    if( $a['order-dir'] == 'asc' ) {
        return $a['distance'] > $b['distance'];
    }
    else {
        return $a['distance'] < $b['distance'];
    }
}

usort( $items, "sort_by_distance" ); // pass the function name as a string