I was working here with some exploded string walks:
array_walk($data, function(&$value)
{
// Transform numerics into appropriate type numbers
if (is_numeric($value))
{
$value = substr_count($value, '.') == 1 ? (float) $value : (int) $value;
}
// Transform dashes into nulls
if ($value == '-')
{
$value = null;
}
});
to transform values into their appropriate types, and some special character handling.
Where I stumbled upon an interesting, huh, bug?
I was amazed, that each entry, that had it's initial value as string(1) '0' ended up being a null.
At first, I thought that the problem relies in (float) and (int) typecasts, though, after debugging:
var_dump((float) '0', (int) '0');
I saw that's not the case, getting the expected result:
float(0)
int(0)
It took me a while, to attempt to debug the, what at the moment appeared to be an obvious, weak type check, but, once I did, I was shocked:
var_dump('-' == 0);
The above expression appears to be:
bool(true)
Now, while writing, I thought I should debug some more, so:
var_dump( '=' == 0 );
var_dump( 'What a lovely nonsense?' == 0 );
var_dump( 0 == 'DAFUQ?' ); // maybe it's because of order? It's PHP, world of miracles, you know...
And, every expression listed above is bool(true).
Okay, maybe that's because internally, mystically PHP casts the expression into a (bool)?
var_dump( (bool) '-' == 0 );
No:
bool(false)
I made a test-case here: http://codepad.org/smiEvsDj
The problem exists in 5.2.5 (codepad), also in 5.4.3 (friend) and also in 5.4.17 (my actual environment).
What is the reason behind this feature / bug / what-the-F-actually-is-this?
You have stumbled upon one of the major complaints that people have about PHP as a language: The fact that the "==" operator is not transitive.
Any string "foo" == TRUE, because the PHP people wanted this to work:
if ($string) {
// do something if $string is set
}
Yet, converting a string to a number (which PHP always tries to do when you use "=="), "foo" == 0!
Of course, TRUE != 0. That is a major pain when dealing with PHP, it's not logical, but it's reality.
It's trying to parse numbers from your strings, not finding any digits and automatically reverting to 0. I think...
e.g. it sees 'What a lovely nonsense?' == 0, sees that you're comparing integers, and tries to convert What a lovely nonsense? to an integer. As there are no numerical digits it defaults to 0, and believes that LHS == RHS so returns true