PHP 仅回显数组中的一项，如果重新加载则不回显

Question

I have an array of values with PHP, Is it possible that when the user first reloads the page, the value should be echoed, but If he reloads the same page again, It should not output two of the same values.

foreach($_SESSION['arrayFolders'] as $value){
    if (in_array($_SESSION['arrayFolders'], $value)) {
        echo 'Do not reload the page, we have already greeted you :)';
    } else {
        echo 'Welcome!';
    }

What I am trying to do with the IF condition is, if the value is already on the session array do not echo it.

NOTE: When the user first enters on the page, he generates an array called $_SESSION['arrayFolders'] .

Any questions feel free to ask.

EDIT 1:

Reverse the in_array method.

...

$_SESSION['arrayFolders'][] = '<a>folder/folder2</a>';

...


foreach($_SESSION['arrayFolders'] as $value){
    if (in_array($value, $_SESSION['arrayFolders'])) {
        echo 'Welcome';
        //Here I should delete the value from the string so that It does not loop again.
    } 

Answer 1

Make it an associative array, where the messages are the keys, and the values are boolean flags indicating whether the message has been shown. When a message is added to the array, the value is false . Then when the page is loaded, you only show these values, and set their values to true to prevent them being shown again.

foreach($_SESSION['arrayFolders'] as $message => &$flag){
    if (!$flag) {
        echo $message;
        $flag = true;
    }
}
unset ($flag); // remove the reference to the array element

Using the reference variable &$flag makes the assignment update the $_SESSION array.