Regarding note of 3-21:
<?php
class myclass {}
$class = 'myclass';
$instance = new $class();
?>
This function could also be used to determine the names of classes defined in a particular file by calling it before and after include. It's hardly a pointless function.
get_declared_classes
(PHP 4, PHP 5, PHP 7, PHP 8)
get_declared_classes — 返回由已定义类的名字所组成的数组
参数
此函数没有参数。
返回值
返回由当前脚本中已定义类的名字组成的数组。
注意:
需要注意的是额外类的出现依赖于你已编译到 PHP 中的库。这意味着你不能使用这些类名定义自己的类。在附录的 预定义类 部分有预定义类的列表。
更新日志
| 版本 | 说明 |
|---|---|
| 7.4.0 | 之前 get_declared_classes() 返回的顺序总是父类在前，子类在后。现在不会这样了。get_declared_classes() 的返回值将不再保证顺序。 |
示例
示例 #1 get_declared_classes() 示例
<?php
print_r(get_declared_classes());
?>以上示例的输出类似于：
Array
(
[0] => stdClass
[1] => __PHP_Incomplete_Class
[2] => Directory
)
参见
- class_exists() - 查类是否已经定义
- get_declared_interfaces() - 返回一个数组包含所有已声明的接口
- get_defined_functions() - 返回所有已定义函数的数组
add a note
User Contributed Notes 10 notes
Anonymous ¶
19 years ago
matt-php at DONT-SPAM-ME dot bitdifferent dot com ¶
20 years ago
The array returned by this function will be in the order the classes were defined / included / required and this order does not appear to change.
For example:
<?PHP
//define classone
class classone { }
//define classtwo
class classtwo { }
//This will show X classes (built-ins, extensions etc) with
//classone and classtwo as the last two elements
print_r(get_declared_classes());
//define classthree
class classthree { }
//...and four
class classfour { }
//Shows the same result as before with class three and four appended
print_r(get_declared_classes());
?>
Output:
Array
(
[0] => stdClass
[1] .... other defined classes....
[10] => classone
[11] => classtwo
)
and...
Array
(
[0] => stdClass
[1] .... other defined classes....
[10] => classone
[11] => classtwo
[12] => classthree
[13] => classfour
)
rmamdaminov at gmail dot com ¶
1 year ago
Note that this function also counts enums.
<?php
enum Bla
{
case Foo;
}
var_dump(get_declared_classes());
?>
Result:
array(116) {
...
[115]=> string(3) "Bla"
}
dexen + goofy _ pl ¶
17 years ago
Summary:
* in PHP 5.1 class names have case preserved
* contrary, in PHP 4.4 class names are downcased, withe exception of a few build-in ones
The get_declared_classes() funcition returns the list of names with case preserved, as of PHP 5.1 series (prolly 5.0 too, but i have no way to test it right now). Since PHP generally is caseless in regard to names of classes, this may come at a surprise. Also, this could potentially break older code asssuming downcased list.
Take extra care when checking for existence of a class. Following example is, potentially, error prone: <?php in_array( $className, $classget_declared_classes() ) ?>
A sure-fire (while slower) way would be to iterate over the array and normalize case to, say, lower:
<?php
$exists = FALSE;
$className = strtolower( $className );
foreach ( get_declared_classes() as $c ) {
if ( $className === strtolower( $c ) ) {
$exists = TRUE;
break;
}
}?>
Optimization of the above snippet is left as a simple excercise to the reader ;)
-- dexen deVries
brain at code dot com ¶
10 years ago
get-declared-classes makes no sense at all, if u maybe, later for production, merge class files in one package file.
lets say: package.php
print_r(get_declared_classes());
class declaredHere { }
print_r(get_declared_classes());
so in this case, the declaredHerr class is defined at the first call of print_r();
because PHP-complier runs a hole file and declare Stuff before running the code.
But (Lovely PHP):
print_r(get_declared_classes());
if(true){
class declaredHere { }
}
print_r(get_declared_classes());
Will print the declaredHere class only in the second print_r.
Its not a Bug it a...
smokey ¶
21 years ago
you cannot remove them. they are "defined", which happens when the class is being loaded from the parser. you just deleted an instance of a class.
matt at mattsoft dot net ¶
18 years ago
classes can't be unloaded. probably not very practical to implement that in a future version. I wouldn't go out of my way to do it if I were zend. you're better off finding a workaround. it's better programming technique to find a way around having to do that anyway.
http://www.zend.com/zend/week/week223.php#Heading10
dcahh at gmx de ¶
16 years ago
This function considers only classes and subclasses. Not subsubclasses.
In fact I have code that provides an abstract class and then classes using this abstract class. Further I have subclasses to my concrete classes - which is why my subclasses are not listed within the returned array.
Jazeps Basko ¶
20 years ago
In PHP5, you don't get declared interfaces by calling this function!!!
To get interfaces you should use get_declared_interfaces(). However, to check if an interface is already defined, you should use class_exists()! This is strange, but PHP team does not think so.
yarco dot wang at gmail dot com ¶
10 years ago
those above comments are too old.
now, whatever the order is, the output will be the same:
<?php
class Test1
{}
print_r(get_declared_classes());
class Test2
{}
print_r(get_declared_classes());
?>
will output the same result.
