Get native type of a variable using get_debug_type() in PHP 8
Before PHP 8, whenever you wanted to get the type of a variable, you could use the native gettype function. Check the examples below.
<?php
$foo = 'bar';
echo gettype($foo); // string
$object = new stdClass;
echo gettype($object); // object
As you can see, the gettype function would return the type of a variable in form of a string. Here are all the possible values returned by the function.
- “boolean”
- “integer”
- “double” (for historical reasons “double” is returned in case of a float, and not simply “float”)
- “string”
- “array”
- “object”
- “resource”
- “resource (closed)” as of PHP 7.2.0
- “NULL”
- “unknown type”
But the problem with gettype is, it returns the long-form types instead of native and more familiar type names. For instance, it returns integer instead of int, double instead of float, and so on.
To mitigate this issues, PHP 8 has introduced a new function called get_debug_type().
The get_debug_type() function
The new get_debug_type function would return the true “native” type of a variable. And as I said earlier, the function would differ from gettype in that it would return native type names, e.g. int rather than integer, double instead of float.
The following table shows what get_debug_type() returns for different values, and what gettype() returns for the same value (if it is different):
| Value | get_debug_type() | gettype() |
|---|---|---|
| 0 | int | integer |
| 0.1 | float | double |
| true | bool | boolean |
| false | bool | boolean |
| “hello” | string | |
| [] | array | |
| null | null | NULL |
| A class with name “Foo\Bar” | Foo\Bar | object |
| An anonymous class | class@anonymous | object |
| A resource | resource (xxx) | resource |
| A closed resource | resource (closed) |
Apart from this, the function would automatically resolve the class names of objects. So, instead of doing it like this using gettype…
<?php
$bar = $arr['key'];
if (!($bar instanceof Foo)) {
throw new TypeError('Expected ' . Foo::class . ' got ' . (is_object($bar) ? get_class($bar) : gettype($bar)));
}
…You can simplify it using get_debug_type (like get_class) like so.
<?php
$bar = $arr['key'];
if (!($bar instanceof Foo)) {
throw new TypeError('Expected ' . Foo::class . ' got ' . get_debug_type($bar));
}
In closing
So, if you want to be more consistent in getting the type of a variable and to avoid situations where types that cannot be handled by existing PHP runtime checking based on parameter types, you should be safe using the get_debug_type instead of gettype function.
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