Question

i m using array_combine() but it display error when in first array there is no value.
how to get rid of this

EDIT:

First array  
Distance_Array
Array
(
    [0] => 
)

School_ID_Array
Array
(
    [0] => 
)
 and i m using
$Coverage_ Array=array_combine($School_ID_Array,$Distance_Array);   

which results

Coverage_ Array
Array
(
    [] => 
)

i want that in first array, if any value is empty , 
then  Coverage_ Array key accept any default key

Answer 1

Use conditions like this:

if (isset($some_var_or_array) && !empty($some_var_or_array)) {
    // some code which using $some_var_or_array value(s)
}

UDATED

Here the function ArrayCombine(), which get three parameters: two arrays and third – the default parameter. The default parameter value will be set to the empty or nulled first array values:

function ArrayCombine($array1, $array2, $default = 0)
{
    foreach ($array1 as $key => $value) {
        if (!isset($value) || empty($value)) {
            $array1[$key] = $default;
        }
    }
    return array_combine($array1, $array2);
}

Here the example:

$Distance_Array = array(
    1 => '',
);

$School_ID_Array = array(
    3 => 4,
);

$Coverage_Array = ArrayCombine($Distance_Array, $School_ID_Array);

var_dump($Coverage_Array);

/*
    var_dump output:
    array(1) {
        [24]=>
            int(4)
    }
*/