对象、json、数组之间的转换

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数组转换

PHP 中，有三种数组类型：

• 索引数组 - 带有数字索引的数组
• 关联数组 - 带有指定键的数组
• 多维数组 - 包含一个或多个数组的数组

array() 函数用于创建数组:

• 索引数组

$indexArr = array("Peter","Ben","Joe");

• 关联数组
  

$assocArr = array("Peter"=>"12","Ben"=>"13","Joe"=>"5");

将数组转化为json格式：

$assocArr = array("Peter"=>"12","Ben"=>"13","Joe"=>"5");    
    var_dump($assocArr);
    var_dump(json_encode($assocArr));

输出：

array(3) {
  ["Peter"]=>
  string(2) "12"
  ["Ben"]=>
  string(2) "13"
  ["Joe"]=>
  string(1) "5"
}
string(35) "{"Peter":"12","Ben":"13","Joe":"5"}"

json转换

<?php
$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';

var_dump(json_decode($json));//转化为对象
var_dump(json_decode($json, true));//转化为数组

?>

输出

object(stdClass)#1 (5) {
  ["a"]=>int(1)
  ["b"]=>int(2)
  ["c"]=>int(3)
  ["d"]=>int(4)
  ["e"]=>int(5)
}
array(5) {
  ["a"]=>int(1)
  ["b"]=>int(2)
  ["c"]=>int(3)
  ["d"]=>int(4)
  ["e"]=>int(5)
}

简单模仿一下json解析

function simple_json_parser($json){
        $json = str_replace("{","",str_replace("}","", $json));
        $jsonValue = explode(",", $json);
        $arr = array();
        foreach($jsonValue as $v){
            $jValue = explode(":", $v);
            $arr[str_replace('"',"", $jValue[0])] = (str_replace('"', "", $jValue[1]));
        }
        return $arr;
    }
    

    $json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';
    $json_parser = simple_json_parser($json);
    $json2arr = json_decode($json, true);

    var_dump($json_parser);
    var_dump($json2arr);

输出

array(5) {
  ["a"]=>
  string(1) "1"
  ["b"]=>
  string(1) "2"
  ["c"]=>
  string(1) "3"
  ["d"]=>
  string(1) "4"
  ["e"]=>
  string(1) "5"
}
array(5) {
  ["a"]=>
  int(1)
  ["b"]=>
  int(2)
  ["c"]=>
  int(3)
  ["d"]=>
  int(4)
  ["e"]=>
  int(5)
}

对象转换

将对象转换为数组

   function objToArr($obj){
        if(!is_object($obj) && !is_array($obj)) {
            return $obj;
        }
        $arr = array();
        foreach($obj as $k => $v){
            $arr[$k] = objToArr($v);
        }
        return $arr;
    }

    $json = '{"a":1, "b":2, "c":3, "d":4, "e":5}';
    $json2obj = json_decode($json);    
    var_dump($json2obj);
    var_dump(objToArr($json2obj));

输出

object(stdClass)#1 (5) {
  ["a"]=>int(1)
  ["b"]=>int(2)
  ["c"]=>int(3)
  ["d"]=>int(4)
  ["e"]=>int(5)
}
array(5) {
  ["a"]=>int(1)
  ["b"]=>int(2)
  ["c"]=>int(3)
  ["d"]=>int(4)
  ["e"]=>int(5)
}