当第二个节点不存在时，处理PHP错误消息？

Question

Hope someone can help with this

I'm using this to grab the first part of my URL

$page_url = perch_page_url(['include-domain' => false,], true); // 
Output the URL of the current page, minus https
$url_parts = explode("/", $page_url); // Split a string by a string

I'm using this technique to grab the first and second nodes of the URL

$first_node = $url_parts[1]; // First part of string 
$second_node = $url_parts[2]; // Second part of string

On my homepage, there isn't a second node, so I get an undefined offset message.

Is there a way to check if the $second_node exists?

I've tried using

if (isset($second_node)) {
echo "$second_node is set so I will print.";
}

and

if (!empty($second_node)) {
echo '$second_node is either 0, empty, or not set at all';  
}

Both if statements only echo after the $second_node has been set? So I still get the error message.

Answer 1

Please use it directly in the if condition and avoid assigning to a variable or assign after checking it in if condition

if (isset($url_parts[2])) { // remove this line $second_node = $url_parts[2]; 
echo "$second_node is set so I will print.";
}

Answer 2

That is because the error is thrown at the initialization of your $second_node variable.

Check if the node exists first, and then declare the variable:

$second_node = ""; // Or whatever
if (isset($url_parts[2]) {
    $second_node = $url_parts[2];
}

Check it here: https://3v4l.org/fRJ7L

Answer 3

You can do something like this:

$second_node = isset($url_parts[2]) ? $url_parts[2] : FALSE;
if ($second_node)
{
    echo "Second node: {$second_node}";
}

This checks if the third index (0-based) of the $url_parts array is set. If yes, it will assign its value to $second_node . If not, it will assign FALSE so you can handle that further down in the code if you need to check it later (again).