常见知识

1. 匿名函数及其作用域

<?php
$message = 'hello';

// 没有 "use"
$example = function () {
    var_dump($message);
};
echo $example(); //NULL

// 继承 $message
$example = function () use ($message) {
    var_dump($message);
};
echo $example(); //string(5) "hello"

// Inherited variable's value is from when the function
// is defined, not when called
// 在函数定义时就确定了,后续改无用
$message = 'world';
echo $example(); //string(5) "hello"

// Reset message
$message = 'hello';

// Inherit by-reference
// 重新定义方法,参数用指针.
$example = function () use (&$message) {
    var_dump($message);
};
echo $example(); //string(5) "hello"

// The changed value in the parent scope
// is reflected inside the function call
// 因为用了指针,后续更改有用
$message = 'world';
echo $example(); //string(5) "world"

// Closures can also accept regular arguments
// 还可以在匿名函数中自定义参数,和从父作用域中共同使用.
$example = function ($arg) use ($message) {
    var_dump($arg . ' ' . $message);
};
$example("hello"); //string(11) "hello world"
?>

参考链接http://php.net/manual/zh/functions.anonymous.php

2. 获取子类的类名

http://www.php-note.com/article/detail/874

3. 递归爆栈 错误提示

Allowed memory size of 134217728 bytes exhausted (tried to allocate 72 bytes) i

来个不限制内存的设置...

程序中设置ini_set('memory_limit', '-1');

或者到php.ini中设置

4. 根据变量获取类名

get_class($base_Model);
//返回 "命名空间\Patient_Model"

5. 配置本地域名

修改apache配置文件/etc/apache/httpd.conf

启动虚拟主机加载,去掉#

# Virtual hosts
Include /private/etc/apache2/extra/httpd-vhosts.conf

然后修改extra/httpd-vhosts

不过笔者改了以后没在vhotst声明的之前的项目都无法访问了.

还会有403权限问题.我把整个项目都777以后,才可以访问.

6. 获取php中定义的所有页面

问题是这样的:我Laravel后台传输给前台很多变量,我需要获取所有值.

get_defined_vars()可以获取页面的所有变量.

7. HTTP_ORIGIN什么时候存在

最近在PHP调用$_SERVER['HTTP_ORIGIN'],发现有时会有,有时不会

默认什么时候有,一般的ajax访问都会有

而如果是直接的页面跳转或资源访问

8. list

<?php

$info = array('coffee', 'brown', 'caffeine');

// Listing all the variables
list($drink, $color, $power) = $info;
echo "$drink is $color and $power makes it special.\n";

// Listing some of them
list($drink, , $power) = $info;
echo "$drink has $power.\n";

// Or let's skip to only the third one
list( , , $power) = $info;
echo "I need $power!\n";

// list() doesn't work with strings
list($bar) = "abcde";
var_dump($bar); // NULL
?>
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