在 PHP 中从 Json 中提取关键元素

Question

我需要在 PHP 中使用 Json 文件，这样我就可以在其主要元素的特定键中进行迭代。

我有这个示例 Json 数据：

[{"A": [
    {
        "name": "object 1",
        "code": "x001",
        "date": "2018-01-01T23:00:00-0600"
    },
    {
        "name": "object 2",
        "code": "x002",
        "date": "2018-01-01T23:00:00-0600"
    },
    {
        "name": "object 3",
        "code": "x003",
        "date": "2018-01-01T23:00:00-0600"
    }
]},{"B": [
    {
        "name": "object 1",
        "code": "y001"
        "date": "2018-01-01T23:00:00-0600"
    },
    {
        "name": "object 2",
        "code": "y002",
        "date": "2018-01-01T23:00:00-0600"
    }
]}]

据我所知，我可以像这样处理 Json 文件（主键 A 和 B 中没有嵌套元素）：

<?php
$url = './data.json';
$data = file_get_contents($url);
echo "<!--- File contents -->\n";
var_dump($data);
$contents = json_decode($data, true);
echo "<!--- Associative Array -->\n";
var_dump($contents);


echo "<!--- BEGIN -->";
foreach ($contents as $element) {
        echo "Name: " . $element['name'] . "\n";
        echo "Code: " . $element['code'] . "\n";
        echo "Date: " . $element['date'] . "\n";
        echo "- - - - - -\n";
}
echo "<!--- END -->";
?>

我要做的是在给定键内调用一个循环，例如，一个循环对应于 B 的所有元素：

    {
        "name": "object 1",
        "code": "y001"
        "date": "2018-01-01T23:00:00-0600"
    },
    {
        "name": "object 2",
        "code": "y002",
        "date": "2018-01-01T23:00:00-0600"
    }

可能会将这些元素提取到第二个关联数组或其他建议的方法...

而预期的结果需要是：

Name: object 1
Code: y001
Date: 2018-01-01T23:00:00-0600
- - - - - -
Name: object 2
Code: y002
Date: 2018-01-01T23:00:00-0600
- - - - - -

忽略 A 元素

Answer 1

请试试这个一站式文件。您可以通过复制此代码自行尝试。

<?php

$data = '[{"A":[{"name": "object 1","code": "x001","date": "2018-01-01T23:00:00-0600"},{"name": "object 2","code": "x002","date": "2018-01-01T23:00:00-0600"},{"name": "object 3","code": "x003","date": "2018-01-01T23:00:00-0600"}]},{"B": [{"name": "object 1","code": "y001","date": "2018-01-01T23:00:00-0600"},{"name": "object 2","code": "y002","date": "2018-01-01T23:00:00-0600"}]}]';

// $url = './data.json';
// $data = file_get_contents($url);
echo "<!--- File contents -->\n";
$contents = json_decode($data, true);
echo "<!--- Associative Array -->\n";
echo "<pre>";
// var_dump($contents);
echo "</pre>";


echo "<!--- BEGIN -->";
echo "<pre>";
foreach ($contents as $element) {

    if(!isset($element['B'])) continue;
    foreach($element as $items){
        foreach($items as $item){
        echo "Name: " . $item['name'] . "\n";
        echo "Code: " . $item['code'] . "\n";
        echo "Date: " . $item['date'] . "\n";
        echo "- - - - - -\n";
        }
    }
    echo "- - - - - -\n";
}
echo "</pre>";
echo "<!--- END -->";

---

输出

Name: object 1
Code: y001
Date: 2018-01-01T23:00:00-0600
- - - - - -
Name: object 2
Code: y002
Date: 2018-01-01T23:00:00-0600
- - - - - -
- - - - - -

Answer 2

你可以用foreach()循环这样做

$array = json_decode($json,1);
//$array[1] for accessing contents of B
echo "<!--- BEGIN -->\n";
foreach($array[1] as $key=>$contents){
   foreach ($contents as $element) {
        echo "Name: " . $element['name'] . "\n";
        echo "Code: " . $element['code'] . "\n";
        echo "Date: " . $element['date'] . "\n";
        echo "- - - - - -\n";
    }
}
echo "<!--- END -->";

7.1.25 - 7.3.4 的输出

<!--- BEGIN -->
Name: object 1
Code: y001
Date: 2018-01-01T23:00:00-0600
- - - - - -
Name: object 2
Code: y002
Date: 2018-01-01T23:00:00-0600
- - - - - -
<!--- END -->

工作演示： https://3v4l.org/ajnOG

Answer 3

此脚本可能会帮助您设计和输出所需的字符串。它适用于$element["B"]。您可以简单地为数组的其他元素编写类似的foreach，例如$element["A"]。

$url = './data.json';
$data = file_get_contents($url);
$output = "<!--- File contents -->\n";
$contents = json_decode($data, true);
$output .= "<!--- Associative Array -->\n";

$output .= "<!--- BEGIN -->\n";
foreach ($contents as $elements) {
    if (!$elements["B"]) {continue;} // You might remove this and add other elements of your inputs such as $elements["A"]
    foreach ($elements["B"] as $key => $element) {
        $output .= "Name: " . $element['name'] . "\n";
        $output .= "Code: " . $element['code'] . "\n";
        $output .= "Date: " . $element['date'] . "\n";
        $output .= "- - - - - -\n";
    }

}
$output .= "<!--- END -->\n";

echo $output;

你可能不需要逐行回显，你可以将它存储在一个变量中，例如$output，最后是echo $output;。

输出：

<!--- File contents -->
<!--- Associative Array -->
<!--- BEGIN -->
Name: object 1
Code: y001
Date: 2018-01-01T23:00:00-0600
- - - - - -
Name: object 2
Code: y002
Date: 2018-01-01T23:00:00-0600
- - - - - -
<!--- END -->