如何显示json字符串的差异？

手动检查并输出：

$a = '{
  "orderID": 773,
  "shopperName": "Трегубенко Егор",
  "shopperEmail": "sinecura92@mail.ru",
  "contents": [
    {
      "productID": 34,
      "productName": "Холодильник, indesit 423jd2",
      "quantity": 1
    },
    {
      "productID": 56,
      "productName": "Наушники, Philips",
      "quantity": 3
    }
  ],
  "orderCompleted": true
}';
$b = '{
  "orderID": 773,
  "shopperName": "Трегубенко Егор",
  "shopperEmail": "sinecura92@mail.ru",
  "contents": [
    {
      "productID": 31,
      "productName": "Стиральная машина bosch",
      "quantity": 2
    },
    {
      "productID": 56,
      "productName": "Наушники, Philips",
      "quantity": 3
    }
  ],
  "orderCompleted": true
}';
$arr1 = json_decode($a, true);
$arr2 = json_decode($b, true);

$result = my_array_compare($arr1, $arr2, 0);

function my_array_compare($arr1, $arr2, $level) {
    $result = [];

    foreach ($arr2 as $key => $value) {
        if (!isset($arr1[$key])) {
            $result[$key] = ['not exist', $value];
        }
        else if ($arr1[$key]!=$value) {
            if (is_array($arr2[$key])) {
                if ($level<1) {
                    $result[$key] = my_array_compare($arr1[$key], $arr2[$key], $level + 1);
                }
                else {
                    $result[$key] = [$arr1[$key], $value];
                }
            }
            else {
                $result[$key] = [$arr1[$key], $value];
            }
        }
    }
    return $result;
}

print_r($result);

$result = compare_contents($arr1['contents'], $arr2['contents']);

function compare_contents($arr1, $arr2) {
    $cArr1 = $cArr2 = $result = [];
    foreach ($arr1 as $item) {
        $cArr1[$item['productID']] = $item['quantity'];
    }
    foreach ($arr2 as $item) {
        $cArr2[$item['productID']] = $item['quantity'];
    }

    foreach ($cArr1 as $key => $value) {
        if (!isset($cArr2[$key])) {
            $result['_left'][$key] = [$value, 'not exist'];
        }
        else if ($value!=$cArr2[$key]) {
            $result['_left'][$key] = [$value, $cArr2[$key]];
        }
    }

    foreach ($cArr2 as $key => $value) {
        if (!isset($cArr1[$key])) {
            $result['_right'][$key] = ['not exist', $value];
        }
        else if ($value!=$cArr1[$key]) {
            $result['_right'][$key] = [$cArr1[$key], $value];
        }
    }

    return $result;
}

print_r($result);

我写了 2 个函数： 1 - 按现有顺序直接比较数组元素；2 - 通过'contents'数组的现有值进行比较（因为这个数组中元素的顺序和数量可能不同）。

功能结果my_array_compare：

Array
(
    [contents] => Array
        (
            [0] => Array
                (
                    [0] => Array
                        (
                            [productID] => 34
                            [productName] => Холодильник, indesit 423jd2
                            [quantity] => 1
                        )

                    [1] => Array
                        (
                            [productID] => 31
                            [productName] => Стиральная машина bosch
                            [quantity] => 2
                        )

                )

        )

)

功能结果compare_contents：

Array
(
    [_left] => Array
        (
            [34] => Array
                (
                    [0] => 1
                    [1] => not exist
                )

        )

    [_right] => Array
        (
            [31] => Array
                (
                    [0] => not exist
                    [1] => 2
                )

        )

)

在函数中，my_array_compare我提供了嵌套级别的比较。

也许不是最优雅的例子，而是一个有效的例子。

这可能不是最简洁的解决方案，但它有效：

    function Fr($aM, $bM, $preKey){
        foreach ($aM as $key => $value){
            foreach ($bM as $key2 => $value2){
                if($key==$key2){
                    if(gettype($value) != "array"){

                        if($value2!=$value){
                            $buff.="<br>$preKey|$key|=>$value :: $preKey|$key2|=>$value2<br>";
                            break;
                        }else{
                            break;
                        }
                    }else{
                        $buff.=Fr($aM[$key], $bM[$key], $preKey."|".$key);
                        break;
                    }
                }
            }   

        }
    return $buff;
    }   
    $a='{
      "orderID": 773,
      "shopperName": "Трегубенко Егор",
      "shopperEmail": "sinecura92@mail.ru",
      "contents": [
        {
          "productID": 34,
          "productName": "Холодильник, indesit 423jd2",
          "quantity": 1
        },
        {
          "productID": 56,
          "productName": "Наушники, Philips",
          "quantity": 3
        }
      ],
      "orderCompleted": true
    }';
    $b='{
      "orderID": 773,
      "shopperName": "Трегубенко Егор",
      "shopperEmail": "sinecura92@mail.ru",
      "contents": [
        {
          "productID": 31,
          "productName": "Стиральная машина bosch",
          "quantity": 2
        },
        {
          "productID": 56,
          "productName": "Наушники, Philips",
          "quantity": 3
        }
      ],
      "orderCompleted": true
    }';
    $aM=json_decode($a, true);
    $bM=json_decode($b, true);   
    echo "<pre>".Fr($aM, $bM, "")."</pre>";

输出：

|contents|0|productID|=>34 :: |contents|0|productID|=>31

|contents|0|productName|=>Холодильник, indesit 423jd2 ::|contents|0|productName|=>Стиральная машина bosch

|contents|0|quantity|=>1 :: |contents|0|quantity|=>2