Three commonly used functions in the PHP SPL standard library

This article mainly introduces the commonly used functions in the PHP SPL standard library. This article focuses on the three functions of spl_autoload_extensions(), spl_autoload_register(), and spl_autoload(). Friends in need can refer to it

The PHP SPL standard library provides some functions for processing such as automatic loading, iterator processing, etc.

spl_autoload_extensions() adds file extensions that can be loaded by spl_autoload()
spl_autoload_register() registers the function into the SPL __autoload function stack.

The code is as follows:

/*test1.php*/
<?php
class Test1
{
}
 
/*test2.lib.php*/
<?php
class Test2
{
}
 
/*test.php*/
<?php
//设置可加载类的文件扩展名
spl_autoload_extensions(".php,.inc.php,.class.php,.lib.php");
//设置include_path,autoload会在这些path中去寻找类文件,可通过PATH_SEPARATOR添加多个path
set_include_path(get_include_path().PATH_SEPARATOR.&#39;libs/&#39;);
//不提供参数，默认实现函数是spl_autoload()
spl_autoload_register();
 
$test1 = new Test1();
$test2 = new Test2();
spl_autoload()它是__autoload()的默认实现，它会去include_path中加载文件(.php/.inc)

The code is as follows:

/*test1.php*/
<?php
class Test1
{
}
 
/*test.php*/
<?php
set_include_path(get_include_path().PATH_SEPARATOR.&#39;libs/&#39;);
spl_autoload(&#39;test1&#39;);
$test1 = new Test1();
spl_autoload_call()调用所有spl_autoload_register注册函数来加载文件

The code is as follows:

/*test1.php*/
<?php
class Test
{
    public function getFilename()
    {
        echo &#39;test1.php&#39;;
    }
}
 
/*test2.lib.php*/
<?php
class Test
{
    public function getFilename()
    {
        echo &#39;test2.lib.php&#39;;
    }
}
 
/*test.php*/
<?php
 
function loader($classname)
{
    if($classname == &#39;Test1&#39;) {
        require __DIR__ . &#39;/test1.php&#39;;
    }
    if($classname == &#39;Test2&#39;) {
        require __DIR__ . &#39;/test2.lib.php&#39;;
    }
}
 
spl_autoload_register(&#39;loader&#39;);
spl_autoload_call(&#39;Test2&#39;);
 
 
$test = new Test();
$test->getFilename(); //test2.lib.php

Other SPL function introduction:
class_implements — Returns the specified class All interfaces implemented.
class_parents — Returns the parents of the specified class.
class_uses — Return the traits used by the given class
iterator_apply — Call a user-defined function for each element in the iterator
iterator_count — Count the number of elements in the iterator
iterator_to_array — Will The elements in the iterator are copied to the array
spl_autoload_functions — Returns all registered __autoload() functions
spl_autoload_unregister — Unregisters registered __autoload() functions
spl_classes — Returns all available SPL classes
spl_object_hash — Returns the hash id of the specified object

If iterator related functions are used:

The code is as follows:

$iterator  = new  ArrayIterator (array( 'recipe' => 'pancakes' ,  'egg' ,  'milk' ,  'flour' ));
 
print_r(iterator_to_array($iterator)); //将迭代器元素转化为数组
echo iterator_count($iterator); //计算迭代器元素的个数
print_r(iterator_apply($iterator, 'print_item', array($iterator)));//为迭代器每个元素调用自定义函数
 
 
function print_item(Iterator $iterator)
{
    echo  strtoupper ( $iterator -> current ()) .  "\n" ;
    return  TRUE ;
}

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