带有嵌套数组的 PHP foreach?

问题描述

我有一个嵌套数组，我想在其中显示结果的子集.例如，在下面的数组中，我想遍历嵌套数组 [1] 中的所有值.

大批([0] => 数组([0] => 一[1] => 数组([0] => 1[1] => 2[2] => 3))[1] => 数组([0] => 两个[1] => 数组([0] => 4[1] => 5[2] => 6))[2] => 数组([0] => 三[1] => 数组([0] => 7[1] => 8[2] => 9)))

我试图使用 foreach 函数，但我似乎无法让它工作.这是我原来的语法(虽然我意识到这是错误的).

$tmpArray = array(array("one",array(1,2,3)),array("two",array(4,5,6)),array("three",array(7,8,9))));foreach ($tmpArray[1] 作为 $value) {回声 $value;}

我试图避免对密钥是否与我要搜索的密钥相同进行变量比较，即

foreach ($tmpArray as $key => $value) {如果 ($key == 1) {回声 $value;}}

有什么想法吗?

解决方案

如果您知道嵌套数组中的级别数，您可以简单地执行嵌套循环.像这样:

//扫描外循环foreach ($tmpArray 作为 $innerArray) {//检查类型如果(is_array($innerArray)){//扫描内循环foreach ($innerArray 作为 $value) {回声 $value;}}别的{//一二三回声 $innerArray;}}

如果您不知道数组的深度，则需要使用递归.请参见下面的示例:

//多维源数组$tmpArray = 数组(数组(一"，数组(1, 2, 3))，数组("二", 数组(4, 5, 6)),数组(三"，数组(7、8、数组(四", 9, 10))));//输出数组displayArrayRecursively($tmpArray);/*** 用缩进显示数组成员的递归函数** @param array $arr 要处理的数组* @param string $indent 缩进字符串*/函数 displayArrayRecursively($arr, $indent='') {如果($arr){foreach ($arr 作为 $value) {如果 (is_array($value)) {//displayArrayRecursively($value, $indent .'--');} 别的 {// 输出echo "$indent $value \n";}}}}

下面的代码仅显示带有特定情况值的嵌套数组(仅限第 3 级)

$tmpArray = 数组(数组(一"，数组(1, 2, 3))，数组("二", 数组(4, 5, 6)),数组(三"，数组(7、8、9)));//扫描外循环foreach ($tmpArray 作为 $inner) {//检查类型如果(is_array($inner)){//扫描内循环foreach ($inner[1] 作为 $value) {echo "$value \n";}}}

I have a nested array in which I want to display a subset of results. For example, on the array below I want to loop through all the values in nested array[1].

Array
(
  [0] => Array
    (
      [0] => one
      [1] => Array
        (
          [0] => 1
          [1] => 2
          [2] => 3
        )
    )

  [1] => Array
    (
      [0] => two
      [1] => Array
        (
          [0] => 4
          [1] => 5
          [2] => 6
        )
    )

  [2] => Array
    (
      [0] => three
      [1] => Array
        (
          [0] => 7
          [1] => 8
          [2] => 9
        )
    )
)

I was trying to use the foreach function but I cannot seem to get this to work. This was my original syntax (though I realise it is wrong).

$tmpArray = array(array("one",array(1,2,3)),array("two",array(4,5,6)),array("three",array(7,8,9)));

foreach ($tmpArray[1] as $value) {
  echo $value;
}

I was trying to avoid a variable compare on whether the key is the same as the key I want to search, i.e.

foreach ($tmpArray as $key => $value) {
  if ($key == 1) {
    echo $value;
  }
}

Any ideas?

解决方案

If you know the number of levels in nested arrays you can simply do nested loops. Like so:

//  Scan through outer loop
foreach ($tmpArray as $innerArray) {
    //  Check type
    if (is_array($innerArray)){
        //  Scan through inner loop
        foreach ($innerArray as $value) {
            echo $value;
        }
    }else{
        // one, two, three
        echo $innerArray;
    }
}

if you do not know the depth of array you need to use recursion. See example below:

//  Multi-dementional Source Array
$tmpArray = array(
    array("one", array(1, 2, 3)),
    array("two", array(4, 5, 6)),
    array("three", array(
            7,
            8,
            array("four", 9, 10)
    ))
);

//  Output array
displayArrayRecursively($tmpArray);

/**
 * Recursive function to display members of array with indentation
 *
 * @param array $arr Array to process
 * @param string $indent indentation string
 */
function displayArrayRecursively($arr, $indent='') {
    if ($arr) {
        foreach ($arr as $value) {
            if (is_array($value)) {
                //
                displayArrayRecursively($value, $indent . '--');
            } else {
                //  Output
                echo "$indent $value \n";
            }
        }
    }
}

---

The code below with display only nested array with values for your specific case (3rd level only)

$tmpArray = array(
    array("one", array(1, 2, 3)),
    array("two", array(4, 5, 6)),
    array("three", array(7, 8, 9))
);

//  Scan through outer loop
foreach ($tmpArray as $inner) {

    //  Check type
    if (is_array($inner)) {
        //  Scan through inner loop
        foreach ($inner[1] as $value) {
           echo "$value \n";
        }
    }
}

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