filter_var_array（） - 未定义的变量

Question

I'm trying to use filter_var_array() and FILTER_CALLBACK to format some numbers, I thought this would work, but it does not:

$item_arr = filter_var_array($item_arr, array(
    'item_number'       => array(
        'filter'    => FILTER_CALLBACK,
        'options'   => array($this, 'number_format')
    )
) );

though this does work:

$item_arr = filter_var_array($item_arr, array(
    'item_number'       => array(
        'filter'    => FILTER_CALLBACK,
        'options'   => function( $num ){
            return number_format( $num );
        }
    )
) );

What's the difference between these two? What's the point of assigning an array() to options?

Answer 1

In the first example you are trying to create a callback for $this->number_format, but I guess you want the global function number_format instead. If you passing a function (unlike an object method) as callback just the function name as a string should getting passed, like this:

$item_arr = filter_var_array($item_arr, array(
    'item_number'       => array(
        'filter'    => FILTER_CALLBACK,
        'options'   => 'number_format'
    )
));

Check the documentation page about callbacks to get more information.

---

If you want to format an array of numbers, the function array_walk() seems fitting better:

array_walk($item_arr, 'number_format');