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Array reference always succeeds

By chx ~ Posted Thu, 07/08/2010 - 06:39

php -r 'var_dump($a["foo"]);var_dump(&$a["foo"]);var_dump($a);'

»

Static properties and variable classnames

By chx ~ Posted Tue, 07/06/2010 - 20:13

Oh no!

<?php
class test {
  static public $foo = 'test1';
  static public $bar = 'test2';
  function foo() {
    print "method foo\n";
  }
}

class test1 {
  function __construct() {
    print "test1 constructor\n";
  }
}
class test2 {
  function __construct() {
    print "test2 constructor\n";
  }
}

function test1() {
  print "test1 function\n";
}
function test2() {
  print "test2 function\n";
}
function foo() {
  print "foo function\n";
  return 'bar';
}

$foo = 'foo';

$a = test::$foo;
new $a();
new test::$foo();
$a();
print test::$foo();
?>

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_FILES array

By chx ~ Posted Sat, 03/13/2010 - 07:53

An <input type="file" name="foo"> produces this

<?php
array (
  'foo' => 
  array (
    'name' => '',
    'type' => '',
    'tmp_name' => '',
    'error' => 4,
    'size' => 0,
  ),
)
?>

$_FILES array. What do you think foo[bar] will produce?

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array_slice confused about negative length

By moshe weitzman ~ Posted Wed, 02/10/2010 - 13:15

Why is the second array below empty? It seems array_splice cannot grok negative length, despite its docs.

<?php
$array = array('a' => '1');

// GOOD
print_r(array_slice($array, 0,  10));

// WTF. Why empty array?
print_r(array_slice($array, 0,  -10)); 
?>

Array
(
    [a] => 1
)
Array
(
)

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26 comments

Identical arrays vs equal arrays

By boombatower ~ Posted Mon, 11/09/2009 - 13:33

There is a small problem when comparing arrays -- you can find arrays where array_diff comes back empty and yet, the arrays are not identical.

<?php
$array1 = array(
  'foo' => 'foo',
  'bar' => 'bar',
);

$array2 = array(
  'bar' => 'bar',
  'foo' => 'foo',
);

var_dump(array_diff($array1, $array2)); // Result: empty array.
var_dump($array1 == $array2); // Result: true.
var_dump($array1 === $array2); // Result: false.
?>

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Numeric and integer keys

By chx ~ Posted Tue, 09/08/2009 - 16:28

<?php
$a = 1;
$b ->$a = 'foo';
var_export((array)$b);
var_export(array(1 => 'foo'));
?>

Results:

array (
  '1' => 'foo',
)array (
  1 => 'foo',
)

Observe the '1'. The array element after casting can not be reached via the [] operator. (And no, "'1'" wont do the trick.)

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2 comments

Even more hexadecimal fun

By chx ~ Posted Fri, 09/04/2009 - 01:29

Some functions working on floats accept hexadecimal numbers while others don't:

<?php
print sin('15');
print sin('0xF');
var_dump(round('15'));
var_dump(round('0xF'));
?>

You will see a float(0) for the second one if your PHP version is lower than 5.3.0. In PHP 5.3.0 and ongoing, both of these functions support hexadecimal numbers, however the explicit casting still does not.

Props go to Stan Vassilev for this one and also in general for being a great source of WTFs :)

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1 comment

Explicit and implict casting

By chx ~ Posted Thu, 09/03/2009 - 23:49

PHP automatically casts strings to integers when doing arithmetic. However, intval($string) and $string + 0 is not the same! The first one works on numbers only, as described under String conversion to numbers in the manual, however, the latter is happy to accept numeric strings which again means that hexadecimal numbers are accepted. Compare print "0xf"+0 to intval("0xf").

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1 comment