php字符串和数组的转换

<?php
// 字符串转数组
$string = "Hello World love Shanghai";
$arr1 = explode(" ", $string);
print_r($arr1);

Array (
[0] => Hello 
[1] => World 
[2] => love 
[3] => Shanghai 
) 

$string="hello world";
$arr1=str_split($string,2);
print_r($arr1)

Array (
 [0] => he 
 [1] => ll 
 [2] => o
 [3] => wo
 [4] => rl 
 [5] => d
 ) 

$arr2= array(‘Hello‘,‘World!‘,‘hh‘,‘oo‘);
$str = implode(" ",$arr2);
print_r($str);

Hello World! hh oo