类中的php回调函数 [英] php callback function in class
问题描述
由于某些原因,我们的托管公司使用了PHP 5.2,甚至没有预先安装mysqli和PDO.
for some reasons, our hosting company used PHP 5.2 and doesn't even have mysqli and PDO pre-installed.
我别无选择,只能重写部分代码以使其与5.2兼容.
I have no choice but to rewrite some part of my code to make it 5.2 compatible.
所以,这是我的问题:
在PHP 5.2中,不支持匿名函数,因此我进行了以下测试以确保我正确地更改了代码:
In PHP 5.2 Anonymous function is not supported, so i did the following test to make sure I'm changing the code correctly:
class foo{
public function toString(){
$arr = array("a", "b");
$arr2 = array("c", "d");
print_r(array_map('mapKeyValue', $arr, $arr2));
}
private function mapKeyValue($v, $k){
return $k."='".$v."'";
}
}
$foo = new foo();
echo $foo->toString();
但是以上内容会给我:
Warning: array_map() expects parameter 1 to be a valid callback, function 'mapKeyValue' not found or invalid function name in ....
PHP Warning: array_map() expects parameter 1 to be a valid callback, function 'mapKeyValue' not found or invalid function name in ....
正确的方法是:
array_map('mapKeyValue', $arr, $arr2);
在课堂上?
PS:是否因为使用PHP 5.2而更改托管公司是一个足够好的理由?(我还剩下大约7个月的合同)
PS: Is it a good enough reason to change hosting company because they use PHP 5.2?(i got a contract with about 7 month left)
推荐答案
使用$this
和一个数组作为回调:
Use $this
and an array as the callback:
array_map( array( $this, 'mapKeyValue'), $arr, $arr2);
而且,可以肯定的是,这已经经过PHP 5.2.17的测试,并且可以正常工作.
And, just to be sure, this is tested with PHP 5.2.17 and is confirmed working.
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