Side Effect in PHP

[Xelene]

Try this.

$x['foo'] = 'foo';
$x['foo']['bar'] = 'bar';
var_dump($x);

 

[Xelene]

It makes sense once you realize what's going on, but it's messy.

$x['foo'] = 'foo';

As $x is uninitialized, the parser reads the [] as an array access and creates an $x as array of 'foo' => 'bar'

$x['foo']['bar'] = 'bar';

$x is now initialized as an array but $x['foo'] is a string within that array so the second set of brackets treated as (rarely) used string accessors. 'bar' is a string that is silently casted to 0 as that is what the string accessor expects and the value of the first character $x['foo'] is set to 'b' (as a range wasn't specified).

It's an odd one, because you'd normally expect the code:

$x['foo']['bar'] = 'bar';

To set a $x -> child_element (foo) -> child_element (bar) to bar. The correct code is actually:

$x = array('foo'=>'foo');
$x['foo'] = array('bar'=>'bar');

(The original value of $x['foo'] gets clobbered)