在php中基于数组元素填充

This is my code.

        if(in_array("1", $mod)){ 
        $res=array('First Name','Insertion','Last Name','Lead Country');}

       if(in_array("2", $mod)){ 
        $res=array('Landline No:','Mobile No:','Lead Country');}

        if(in_array("3", $mod)){ 
        $res=array('City','State','Country','Lead Country');}

        if(in_array("4", $mod)){ 
        $res=array('Email','Lead Country');}

        return $res;

Upto this it works fine. But if the array contains more than one value say (1,3) I need to return both results of 1 and 3.

eg: if the array is like this

    array([0]=>1 [1]=>3)

then

    $res=array('First Name','Insertion','Last Name','City','State','Country','Lead Country') 

But if there are 2 lead country only one should be displayed how to do this? Pls help me.

Here's an example that uses a function to add the elements, only if they don't already exist:

    function addItems($items, $arr)
    {
        foreach($items as $value)
        {
            if(!in_array($value, $arr))
            {
                $arr[] = $value;
            }
        }

        return $arr;
    }

    $res = array();

    if(in_array("1", $mod)){ 
    $res = addItems(array('First Name','Insertion','Last Name','Lead Country'), $res);}

    if(in_array("2", $mod)){ 
    $res = addItems(array('Landline No:','Mobile No:','Lead Country'), $res);}

    if(in_array("3", $mod)){ 
    $res = addItems(array('City','State','Country','Lead Country'), $res);}

    if(in_array("4", $mod)){ 
    $res = addItems(array('Email','Lead Country'), $res);}

    return $res;

Here's another way of doing it which is more OOP and is probably a bit more logical because it doesn't keep passing the whole array back and to, instead it uses an object which holds the array, and has a method to add to it, and get the final result:

    class ItemsManager
    {
        protected $items = array();

        public function addItems($items)
        {
            foreach($items as $value)
            {
                if(!in_array($value, $this->items))
                {
                    $this->items[] = $value;
                }
            }
        }

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

    $im = new ItemsManager();

    if(in_array("1", $mod)){ 
    $im->addItems(array('First Name','Insertion','Last Name','Lead Country'));}

    if(in_array("2", $mod)){ 
    $im->addItems(array('Landline No:','Mobile No:','Lead Country'));}

    if(in_array("3", $mod)){ 
    $im->addItems(array('City','State','Country','Lead Country'));}

    if(in_array("4", $mod)){ 
    $im->addItems(array('Email','Lead Country'));}

    return $im->getItems();

Use array_merge:

$res = array();
if(in_array("1", $mod)){
    $res=array_merge($res, array('First Name','Insertion','Last Name','Lead Country'));
}

// and so on ...

return $res;

Use array_merge to build the result...

    $res = array();

    if(in_array("1", $mod)) { 
        $res = array_merge($res, array('First Name','Insertion','Last Name','Lead Country'));
    }

    // etc