What do increment operators do in arrays?

Question

Accidentally I was creating a PHP script and unintentionally put an increment operator in a variable whose type is array.

To my surprise, no error was shown by PHP.

I did some tests and found that really this does not generate error for type variables array.

Testing:

$dados['nome'] = 'wallace';

$empty = array();

$dados++;

$empty--;

print_r($dados);

print_r($empty);

Upshot:

Array
(
    [nome] => wallace
)
Array
(
)

Before someone makes a comment or questions things like "And why did you expect it to return an error?" I explain to you.

That I know increment and decrease operators work for values like int (except for the increment in PHP, which increments letters :p).

So, in the case of sum of values int with array, the expression below would return a Fatal Error:

$dados = array();

$dados + 1

Error generated:

Fatal error: Unsupported operand types

The sum operator in arrays operate so that the values of the array are inserted into the array right, if there are no:

['nome' => 'wallace'] + ['idade' => 23, 'nome' => 'Wayne']

Upshot:

['nome' => 'wallace', 'idade' => 23]

So I have a few questions:

• Why PHP does not generate any warning or error when using increment or decrement operators in arrays?

• This could be considered a bug?

• Is there any utility in using the increment operator in array that I haven’t noticed?

Answer 1

Increment/decrement operators affect only numbers and strings. Arrays, objects and resources are not affected. Decreasing NULL does not generate effects, but incrementing results in 1.

http://php.net/manual/en/language.operators.increment.php

Answer 2

No error occurs when using the in/down operator in an array or object because nothing is affected by the documentation says:

Note: The increment/decrement Operators only affect Numbers and strings. Arrays, Objects and Resources are not affected.