Ordinary Web Guy

Just a follow up that I indeed deferred to my post: in_array PHP Function Bug.

I posted the said blog post in PHPUGPH and lead me to fully understand that it was not a bug. As Cruizer said:

if it’s not a bug, then it’s a gotcha. i don’t think that would be obvious to any programmer. bad design, i’d say.

I definitely agree with that statement.

To clear up everything that it was not a bug. See code:

$str = “this is a string”;

if ($str == 0) {
print “true”;
} else {
print “false”;
} # end if

Output: true

Wonder why the output is “true”?
See here: http://www.php.net/manual/en/types.comparisons.php

In addition, RJ said:

As I understand the checking by PHP for the loose comparison of a string and an integer, the PHP engine will call the intval() function for the string before comparing it with the integer. Therefore “any string” == 0 will actually be intval(“any string”) == 0 which will result to 0 == 0. It means that it is not a boolean comparison.

Again, that’s not a bug, gotcha, or whatever you call it but instead a bad design.

See the code:

<?php
$array1 = array(‘php’, ‘java’, ‘ruby’, ‘asp’);
$array2 = array(‘php’ => ‘PHP.net’, ‘java’ => ‘java.com’, 0 => ‘javascript’, 1 => ‘actionscript’);

foreach ($array2 as $key => $value) {
if ( in_array($key, $array1) ) {
print “in array: $key <br />”;
} else {
print “not in array: $key <br />”;
} # end if

} # end foreach

?>

Output:
in array: php
in array: java
in array: 0
not in array: 1

Expected Output:
in array: php
in array: java
not in array: 0
not in array: 1

Though the expected output above can be achieve via supplying TRUE to its third paramater which will set strict typing comparison between the value and array:

<?php
$array1 = array(‘php’, ‘java’, ‘ruby’, ‘asp’);
$array2 = array(‘php’ => ‘PHP.net’, ‘java’ => ‘java.com’, 0 => ‘javascript’, 1 => ‘actionscript’);

foreach ($array2 as $key => $value) {
if ( in_array($key, $array1, TRUE) ) {
print “in array: $key <br />”;
} else {
print “not in array: $key <br />”;
} # end if

} # end foreach

?>

How come that there’s a “0″ value on array $array1? That’s why I consider it a bug. I don’t know if someone has already experience this. I hope somebody could further explain this to me. I’ll also post this bug at PHP.net.

Note:
The script runs in PHP Version: 5.1.1