Python/PHP/JS對象與json資料的轉換key順序問題

1、PHP關聯數組與json資料轉換前後key的順序不變

<?php

// obj -> json
$obj1 = [
    'name'=>'Tom',    
    'age'=> 23,
];

$obj2 = [
    'age'=> 23,
    'name'=>'Tom',
];

print_r(json_encode($obj1));
// {"name":"Tom","age":23}

print_r(json_encode($obj2));
// {"age":23,"name":"Tom"}


// json -> obj
print_r(json_decode('{"name":"Tom","age":23}'));
// ([name] => Tom [age] => 23)

print_r(json_decode('{"age":23,"name":"Tom"}'));
// ([age] => 23 [name] => Tom)      

2、

Python

字典結構與json轉換後3.6之前順序不一緻，之後順序保持一緻

import json

# obj -> json
obj1 = {"age":23,"name":"Tom"}
print(json.dumps(obj1))
# {"age": 23, "name": "Tom"}

obj2 = {"name":"Tom", "age":23}
print(json.dumps(obj2))
# python3.7 {"name": "Tom", "age": 23}
# python3.6.5 {"name": "Tom", "age": 23}
# python2.7 {"age": 23, "name": "Tom"}


# json -> obj
arr1 = json.loads('{"age":23,"name":"Tom"}')
print(arr1)
# {'age': 23, 'name': 'Tom'}

arr2 = json.loads('{"name":"Tom", "age":23}')
print(arr2)
# python3.7 {'name': 'Tom', 'age': 23}
# python3.6.5 {"name": "Tom", "age": 23}
# python2.7 {u'age': 23, u'name': u'Tom'}      

Python 3.6 開始dict字典開始變得有序

[Python-Dev] Python 3.6 dict becomes compact and gets a private version; and keywords become ordered

3、JS資料對象和json資料轉換之後key順序保持不變

// obj -> json
var obj1 = {"age":23,"name":"Tom"}
var obj2 = {"name":"Tom", "age":23}

console.log(JSON.stringify(obj1));
// {"age":23,"name":"Tom"}

console.log(JSON.stringify(obj2));
// {"name":"Tom","age":23}

// json -> obj
console.log(JSON.parse('{"age":23,"name":"Tom"}'));
// { age: 23, name: 'Tom' }

console.log(JSON.parse('{"name":"Tom", "age":23}'));
// { name: 'Tom', age: 23 }