Simple array_diff not working - php

Question

I have 2 arrays.
The first one is $teach_array and the second one is $langs_array.
Their respective values are:
$teach_array : Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )
$langs_array : Array ( [0] => 2 [1] => 3 )
Im trying to return a new array containing all the entries from $teach_array that are not present in $langs_array.
So the end result should be: Array ( [0] => 1 [3] => 4 [4] => 5 )
I have tried using a couple of methods including :
Option 1
$result = array_diff($teachArray, $language_1d_array);
This still returns all the values of $teach_array.
Option 2
$result = array_diff_key($teachArray, $language_1d_array);
However, this only returns Array ( [2] => 3 [3] => 4 [4] => 5 ) which is not correct.
Option 3
$result = array_values(array_diff_key($teachArray, $language_1d_array));
This returns the same result as Option 2. I also tried using only array_diff instead of array_diff_key and it returns the same result as Option 1.
I did a var_dump on both of my arrays and here is the result.
$teach_array : array(5) { [0]=> string(5) " 1 " [1]=> string(5) " 2 " [2]=> string(5) " 3 " [3]=> string(5) " 4 " [4]=> string(5) " 5 " }
$lang_array : array(2) { [0]=> string(1) "2" [1]=> string(1) "3" }

Answer 1

hope you have already found the solution, but just in case I want to point you on following.
Blockquote
I did a var_dump on both of my arrays and here is the result.
$teach_array : array(5) { [0]=> string(5) " 1 " [1]=> string(5) " 2 " [2]=> string(5) " 3 " [3]=> string(5) " 4 " [4]=> string(5) " 5 " }
$lang_array : array(2) { [0]=> string(1) "2" [1]=> string(1) "3" }
No single value from $teach_array matches any value of $lang_array.
Because there are differently formatted values, one array contains whitespaces before and after the value you want to match " 2 ".
var_dump($teach_array) => array(5) { [0]=> string(5) " 4 " ... }
var_dump($lang_array) => array(5) { [0]=> string(1) "2" ... }
I guess you have some whitespaces included. Please try again with:
$diff = array_diff(array_map('trim', $teach_array), $lang_array);

Answer 2

PHPTester just tested yours, works fine for me..?
$teachArray =[1,2,3,4,5];
$langsarray =[2,3];
$result = array_diff($teachArray,$langsarray);
print_r($result);
works and prints 1, 4, 5 for me.
BUT...here's a solution for what you're trying to acquire: the values in teacher array that are not in langs
$new_array = array();
foreach($teach_array as $item){ // Loop the teacher_array
if(!in_array($item,$langs_array)){ // If the teach_array value doesn't exist in the lang_array, add the value
$new_array[] = $item;
}
}

Answer 3

I'm sure theres a more elegant way, but this works:
$teach = [1, 2, 3,4, 5];
$langs = [2, 3];
$result = [];
foreach ($teach as $key => $t) {
if (!in_array($t, $langs)) {
$result[$key] = $t;
}
}
var_dump($result);

Answer 4

This is (basically) what you say you have. It works for me:
<?php
$fred = array(0=>1, 1=>2, 2=>3, 3=>4, 4=>5);
$bert = array(0=>2, 1=>3);
$res = array_diff($fred, $bert);
print_r($res);