Why are these two objects equal (==)?

Question

In PHP, I have two objects, they are different because of the variable $ _frets (x is the string "x"), but PHP says

($o1 == $o2) == TRUE. 

Why?

Dump $o1 :

 guitarChord Object ( [_guitarChord:guitarChord:private] => [_chord:guitarChord:private] => chord Object() [_baseFret:guitarChord:private] => 0 [_frets:guitarChord:private] => Array ( [0] => x [1] => 0 [2] => 2 [3] => 2 [4] => 2 [5] => x ) [_tuning:guitarChord:private] => tuning Object() [currVariation] => 0 [nextVariation] => [prevVariation] => ) 

Dump $o2 :

 guitarChord Object ( [_guitarChord:guitarChord:private] => [_chord:guitarChord:private] => chord Object() [_baseFret:guitarChord:private] => 0 [_frets:guitarChord:private] => Array ( [0] => x [1] => 0 [2] => 2 [3] => 2 [4] => 2 [5] => 0 ) [_tuning:guitarChord:private] => tuning Object() [currVariation] => 0 [nextVariation] => [prevVariation] => ) 

EDIT:

Therefore, the reason is that ("x" == 0) = TRUE . Can someone tell me why?

Answer 1

Does x stand for string or does x mean null? If this value is zero, then this is my theory: on the page "Comparison Pages" there is a transcription of the algorithm for comparing the array in Example No. 1. Based on this, I would suggest that in your case, what eventually happens is a comparison between 0 and zero. According to the table above, when null is compared with anything, it is converted to bool. Thus, you end the comparison 0 (false) to null (false), as a result of which the two arrays are considered equal.