如何将if if语句转换为三元运算符？

I have a piece of code and I want to convert it to ternary operator. Can anyone help? It has 1 if and 2 else if conditions so I am having trouble converting it. Here is my code.

if ($this->session->data['desired_service']==1){
    echo 'Home Delivery';
} else if ($this->session->data['desired_service']==2){
    echo 'Take Away';
} else if ($this->session->data['desired_service']==3){
    echo 'DinIN';
}

Here is the code that I have used so far.

$service = ( $this->session->data['desired_service']== 1 ) ? "Home Delivery" : ( $this->session->data['desired_service'] == 2 ) ? "Take Away" : ( $this->session->data['desired_service'] == 3 ) ? "DinIN";

But it is giving me a syntax error.

echo ($this->session->data['desired_service'] == 3) ? 'DinIN' : (($this->session->data['desired_service']==1) ? 'Home Delivery' : ($this->session->data['desired_service'] == 2) ? 'Take Away' : '');

Explanation:

Use nested ternary operator.

If variable equal to 3, print 'DinIN'    
else : two cases:
if 1 : Home Delivery
else : Take Away

Demos:

if value is 1

If value is 2

if value is 3

Another solution

Use predefined array:

Get all your options in an array and add

1,2 and 3 as keys.

Check array with isset and the variable.

If it is set, print it, else blank.

Purpose solved.

<?php
$arr = array();
$arr[1] = 'Home Delivery';
$arr[2] = 'Take Away';
$arr[3] = 'DinIN';
echo isset($arr[$this->session->data['desired_service']]) ? $arr[$this->session->data['desired_service']] : '';
?>

This is not a good example of when to use ternary operators. Personally, looking at your data - I would use a switch statement, as it will be easier to read and add more options to.

switch($this->session->data['desired_service']){

    case '1':
        $service = "Home Delivery";
        break;

    case '2':
        $service = "Take Away";
        break;

    case '3':
        $service = "DinIN";
        break;

}