Update user meta - array - arrays

Question

I'm developing comments sections for my user profile and I'm giving an option to user to make comment visible or not.
I've created an array:
$comment = array($comment_name, $comment_text, $time, $visible);
Where $visible is false value at default.
And then I add_user_meta
add_user_meta($user->ID, 'recommend_comment', $comment);
This is working perfect for me, I've got an array of comments displayed.
Now I want to update array with $visible = true if user clicks on button but not sure how to access specific array row with update_user_meta.
I tried with:
update_user_meta($user->ID, 'recommend_comment', $prikazi, [2]);
But that's not working. Any idea how to make this?

Answer 1

You can use update_user_meta() for adding and/or updating, see reference: update_user_meta
To update visible you can do:
$comment = get_user_meta( $user->ID, 'recommend_comment', TRUE );
if( !empty( $comment ) ) {
$comment[3] = FALSE;
update_user_meta( $user->ID, 'recommend_comment', $comment );
}
To improve it a bit you could instead use keys in the array, for example:
$comment = array( 'name' => $comment_name, 'text' => $comment_text, 'time' => $time, 'visible' => $visible);
// And then you can access with:
$comment['visible'] = TRUE;
UPDATE: example with a list of comments:
$comments = array(
array( 'name' => 'AAA', 'text' => 'Just a comment', 'time' => '12:50', 'visible' => FALSE ),
array( 'name' => 'BBB', 'text' => 'Another one', 'time' => '14:10', 'visible' => TRUE ),
);
// Create/updates the comments
update_user_meta( $user->ID, 'recommend_comment', $comments );
// ...
// Load the comments
$comments = get_user_meta( $user->ID, 'recommend_comment', TRUE );
if( !empty( $comment ) ) {
// then you can manipulate them with:
$comments[1]['visible'] = FALSE;
// and update the meta as before
update_user_meta( $user->ID, 'recommend_comment', $comments );
}

Answer 2

This works for me.
//delete_user_meta(get_current_user_id(), 'watchlist');
$new_value = $_GET['id'];
if(empty($new_value)){
echo 'No value';
die();
}
$watchlist = get_user_meta( get_current_user_id(), 'watchlist', true);
if( !empty( $watchlist ) ) {
$check_value = unserialize( $watchlist );
// Check if value exists
if( in_array( $new_value, $check_value ) ){
echo 'Already exists';
}else{
$check_value[] = $new_value;
update_user_meta( get_current_user_id(), 'watchlist', serialize( $check_value ) );
}
}else{
update_user_meta( get_current_user_id(), 'watchlist', serialize( [$new_value] ));
}
print_r(unserialize( $watchlist ));