ERROR: using '$this' when not in object context [closed] - php

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I have been coding and improving the code jszobody provided me that can found on this LINK which It makes me to be my refference but it results me to an error Fatal error: Using $this when not in object context
PHP:
<?php
function getAllPossiblePermutations($mdArray, $firstTime=true, $tempArray=array())
{
// initialize results array
if ($firstTime)
{
$this->permutationsResultsArray = array();
}
// find first sub array and iterate through it
$thisArray = array_shift($mdArray);
foreach ($thisArray as $key => $elem)
{
// if this number has already been used skip this possible permutation
if (in_array($elem, $tempArray))
{
continue;
}
$tempArray[] = $elem;
if (count($mdArray) == 0)
{
$this->permutationsResultsArray[] = $tempArray;
}
else
{
$this->getAllPossiblePermutations($mdArray, false, $tempArray);
}
array_pop($tempArray);
}
}
$traits = array
(
array('Happy', 'Sad', 'Angry', 'Hopeful'),
array('Outgoing', 'Introverted'),
array('Tall', 'Short', 'Medium'),
array('Handsome', 'Plain', 'Ugly')
);
print_r(getAllPossiblePermutations($traits));
?>
EXPECTED OUTPUT:
Array ( [0] => HappyOutgoingTallHandsome 1 => HappyOutgoingTallPlain [2] => HappyOutgoingTallUgly [3] => HappyOutgoingShortHandsome [4] => HappyOutgoingShortPlain [5] => HappyOutgoingShortUgly [6] => HappyOutgoingMediumHandsome [7] => HappyOutgoingMediumPlain [8] => HappyOutgoingMediumUgly [9] => HappyIntrovertedTallHandsome [10] => HappyIntrovertedTallPlain [11] => HappyIntrovertedTallUgly [12] => HappyIntrovertedShortHandsome [13] => HappyIntrovertedShortPlain [14] => HappyIntrovertedShortUgly [15] => HappyIntrovertedMediumHandsome [16] => HappyIntrovertedMediumPlain [17] => HappyIntrovertedMediumUgly [18] => SadOutgoingTallHandsome [19] => SadOutgoingTallPlain [20] => SadOutgoingTallUgly [21] => SadOutgoingShortHandsome [22] => SadOutgoingShortPlain [23] => SadOutgoingShortUgly [24] => SadOutgoingMediumHandsome [25] => SadOutgoingMediumPlain [26] => SadOutgoingMediumUgly [27] => SadIntrovertedTallHandsome [28] => SadIntrovertedTallPlain [29] => SadIntrovertedTallUgly [30] => SadIntrovertedShortHandsome [31] => SadIntrovertedShortPlain [32] => SadIntrovertedShortUgly [33] => SadIntrovertedMediumHandsome [34] => SadIntrovertedMediumPlain [35] => SadIntrovertedMediumUgly [36] => AngryOutgoingTallHandsome [37] => AngryOutgoingTallPlain [38] => AngryOutgoingTallUgly [39] => AngryOutgoingShortHandsome [40] => AngryOutgoingShortPlain [41] => AngryOutgoingShortUgly [42] => AngryOutgoingMediumHandsome [43] => AngryOutgoingMediumPlain [44] => AngryOutgoingMediumUgly [45] => AngryIntrovertedTallHandsome [46] => AngryIntrovertedTallPlain [47] => AngryIntrovertedTallUgly [48] => AngryIntrovertedShortHandsome [49] => AngryIntrovertedShortPlain [50] => AngryIntrovertedShortUgly [51] => AngryIntrovertedMediumHandsome [52] => AngryIntrovertedMediumPlain [53] => AngryIntrovertedMediumUgly [54] => HopefulOutgoingTallHandsome [55] => HopefulOutgoingTallPlain [56] => HopefulOutgoingTallUgly [57] => HopefulOutgoingShortHandsome [58] => HopefulOutgoingShortPlain [59] => HopefulOutgoingShortUgly [60] => HopefulOutgoingMediumHandsome [61] => HopefulOutgoingMediumPlain [62] => HopefulOutgoingMediumUgly [63] => HopefulIntrovertedTallHandsome [64] => HopefulIntrovertedTallPlain [65] => HopefulIntrovertedTallUgly [66] => HopefulIntrovertedShortHandsome [67] => HopefulIntrovertedShortPlain [68] => HopefulIntrovertedShortUgly [69] => HopefulIntrovertedMediumHandsome [70] => HopefulIntrovertedMediumPlain [71] => HopefulIntrovertedMediumUgly [72] => )
where did I go wrong?

Answer 1

You have a lot of referemces to class variables, like this:
$this->permutationsResultsArray = array();
And PHP complains since this function is not a method in a class. It will work if you just remove this-> so you get:
$permutationsResultsArray = array();
In addition when you are all done you never really return the result.. Like this:
return $permutationsResultsArray;
There is a problem with it though. You are recusing and you don't create that array except in the first round but your code uses it as if it was defined.
BTW: Your function could be much easier with 3 foreach loops:
function getCombinations($traits)
{
$combinations = array('');
foreach( $traits as $trait_level ) {
$new_combinations = array();
foreach ( $combinations as $comb ) {
foreach ( $trait_level as $trait ){
$new_combinations[] = "$comb $trait";
}
}
$combinations = $new_combinations;
}
return $combinations;
}

Answer 2

A function doesn't have a self referential $this. Actually, removing all your $this-> references and make $tempArray a pass by reference instead of by value, your code should work...
function getAllPossiblePermutations($mdArray, $firstTime=true, &$tempArray=array())