in_array() expects parameter 2 to be array - php

Question

I have this idea of an multiarray with my files sorted into different groups/arrays.
Thinking it would be the easiest and most clean way to check what file we're inside, and should the navigation state be set to active on navigation tab 1,2 or 3?
I have this array;
Array
(
[home] => Array
(
[0] => index.php
[1] => something.php
)
[tour] => Array
(
[0] => tour.php
)
[tutorials] => Array
(
[0] => tutorials.php
)
)
The idea is, if i click on the home navigation button it goes to the index.php and a function checks whether it's the Home button that needs the active state, or the Tour button. In this case its the Home button.
[home] => Array
(
[0] => index.php
I made this function
function findNavigationActive($tap, $filename) {
if(in_array($filename, $topNavigationPages[$tap])) {
return 1;
}
return 0;
}
it should check, if index.php ($filename) is in the Home ($tap) array or navi-tap, then return 1. Unfortunately i get this error insted;
Warning: in_array() expects parameter 2 to be array, null given in /project/../../topNavigationHandler.php on line 21
What am I doing wrong?
FIXED
Used global $topNavigationPages; outside the function, and set $topNavigationPages values (array) beneath, and again used global $topNavigationPages inside the function to pull the array inside.
Thanks #tombs !

Answer 1

What this error means is that the second parameter isn't an array, therefore you can try something like this.:
if (is_array($topNavigationPages[$tap])) {
if(in_array($filename, $topNavigationPages[$tap])) {
return 1;
}
}
return 0;
You can do this without nesting the if loops by using a strict and operator.
Hope this helps
Note:
To resolve your scope issue you can use either a global value or a constant. To use a constant use the 'define' function, for a global declare the variable as such at the beginning of your file and in every subsequent function that you use it in. I strongly recommend using a constant.