PHP在数组中存储匿名函数(类上下文)
我知道在PHP中可以将匿名函数存储为数组值,但为什么它在类上下文中返回NULLPHP在数组中存储匿名函数(类上下文),php,arrays,function,class,anonymous,Php,Arrays,Function,Class,Anonymous,我知道在PHP中可以将匿名函数存储为数组值,但为什么它在类上下文中返回NULL class firstClass { public static $functions = array(); function __construct() { self::$functions += array( "echo" => function( $text ) { echo $text; }, "fruit" => "apple" ); }
class firstClass {
public static $functions = array();
function __construct()
{
self::$functions += array( "echo" => function( $text ) { echo $text; }, "fruit" => "apple" );
}
}
class secondClass {
function __construct()
{
var_dump( firstClass::$functions ); // returns array(1){ ["fruit"] => string(5) => "apple" )
var_dump( firstClass::$functions["echo"] ); // returns NULL
}
}
$class = new firstClass;
第一类构造函数从不调用,您使用的是一个静态变量有趣的是,您得到的是NULL-当我测试代码时,我得到了预期的结果,即notnull。 尝试下面的代码,也许这可以工作:如果没有,尝试升级您的PHP版本
// ----------------------------------------------------
// First try with a simple array, outside a class
// ----------------------------------------------------
$test_array = array(
"string" => "some string" ,
"function" => function() {
echo 'i am an anonymous function outside a Class';
}
);
var_dump($test_array);
// ----------------------------------------------------
// Now try in a Class context
// ----------------------------------------------------
class classContext {
public static $functions = array();
public function __construct() {
self::$functions += array(
"string" => "some string in classContext" ,
"function" => function() {
echo 'i am an anonymous function inside a Class';
}
);
}
}
class secondClass {
public function __construct() {
var_dump(classContext::$functions);
var_dump(classContext::$functions['function']);
}
}
new classContext;
new secondClass;
结果如下:
array(2) {
["string"]=>
string(11) "some string"
["function"]=>
object(Closure)#1 (0) {}
}
array(2) {
["string"]=>
string(27) "some string in classContext"
["function"]=>
object(Closure)#3 (1) {
["this"]=> object(classContext)#2 (0) {}
}
}
object(Closure)#3 (1) {
["this"]=> object(classContext)#2 (0) {}
}
没有调用第一个类的构造函数。对不起,我忘记添加初始化。但是一个正常值确实起作用,这很奇怪..我的荣幸@Ralph: