PHP访问数组中的元素

Question

我有一个看起来像这样的数组：

Array
(
    [0] => Array
        (
            [id] => Classify
            [classification] => Array
                (
                    [0] => Array
                        (
                            [class] => negative
                            [p] => 0.0650294
                        )

                    [1] => Array
                        (
                            [class] => positive
                            [p] => 0.934971
                        )

                )

            [text] => Understanding if a text is positive or negative is easy for humans, but a lot harder for computers. We can “read between the lines”, get jokes and identify irony. Computers aren’t quite there yet but the gap is quickly closing in.
        )

)

如何获得positive negative ？

Answer 1

对外部数组进行数字索引（具有一个元素，一个关联数组），并且这两个值是数组classification包含的数组元素的组成部分，该数组classification也被数字索引，其元素为关联数组。

// By iteration, assuming an unknown number of classifications
foreach ($array[0]['classification'] as $classification) {    
  echo $classification['class'];
  echo $classification['p'];
}

// Or direct access to the elements
echo $array[0]['classification'][0]['class']; // negative
echo $array[0]['classification'][0]['p']; // 0.0650294
echo $array[0]['classification'][1]['class']; // positive
echo $array[0]['classification'][1]['p']; // 0.934971

Answer 2

$array[0]['classification'][0]['p']和$array[0]['classification'][1]['p']访问双精度值。

$array[0]['classification'][0]['class']和$array[0]['classification'][1]['class']来访问“正”和“负”字符串

Answer 3

如果最顶层的数组中有多个元素，则必须解析每个元素：

foreach($item in $array)
    foreach($classification in $item['classification'])
        echo $classification['class'];

Answer 4

print $arr[0]['classification'][0]['class'];
print $arr[0]['classification'][1]['class'];

Answer 5

print $array[0]['classification'][0]['class'];
print $array[0]['classification'][1]['class'];

只要它总是相同数量的分类...