如何在函数中传递数组索引并在函数中检查此索引是否设置为php

Question

I have an associative array in php name as

$formData =array(
    "first"=>"John",
    "second"=>"George",
    "thirld"=>"Harry",
    "fourth"=>"Tom"
);

and a function called isExist($v) as

function isExist($v) {
    if(isset($v)) {
        return $v;
    } 
    return ""; 
}

now i want that this function check either array have index value set or not i.e if I call the function as

echo isExist($formData['apple']);

then it must print an empty string. How to achieve this? Thanks in advanced.

Answer 1

There is no way you can achieve this with passing $formData['apple'] you need to pass the array and index separately

function isExist($array,$index){
    if(isset($array[$index])){
    return $index;
   } 
  return ""; 
}

The error will be raised before it ever had the chance to get in the function because you already called it when you were passing it in as parameter. Use it like this instead

isExist($formData,'apple');