PHP two-dimensional array removes null values

In PHP development, we often use two-dimensional arrays. A two-dimensional array is an array with multiple arrays, each of which can contain a different number of elements. But sometimes we need to remove certain null values ​​​​in a two-dimensional array. In this case, we can use some simple methods to achieve it.

Method 1: Use foreach to loop through the array

We can use foreach to loop through the two-dimensional array, and then use the array_filter function to remove null values ​​​​in each array. Here is a sample code:

<?php

// 定义二维数组
$array = array(
  array('a', 'b', '', 'c'),
  array('', 'd', 'e'),
  array('f', '', 'g', 'h', 'i')
);

// 使用 foreach 循环遍历数组
foreach ($array as $key => $value) {
  // 使用 array_filter 函数去除每个数组中的空值
  $array[$key] = array_filter($value);
}

// 打印处理后的二维数组
print_r($array);

?>

Output result:

Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
            [3] => c
        )

    [1] => Array
        (
            [1] => d
            [2] => e
        )

    [2] => Array
        (
            [0] => f
            [2] => g
            [3] => h
            [4] => i
        )

)

In this example, we use the foreach loop to traverse the two-dimensional array. In each loop, use the array_filter function to remove null values ​​in each subarray. Finally, the processed two-dimensional array is returned.

Method 2: Use the array_map function to traverse the array

We can also use the array_map function to traverse the two-dimensional array, and then use the array_filter function to remove null values ​​​​in each array. Here is a sample code:

<?php

// 定义二维数组
$array = array(
  array('a', 'b', '', 'c'),
  array('', 'd', 'e'),
  array('f', '', 'g', 'h', 'i')
);

// 使用 array_map 函数遍历数组
$array = array_map(function($value) {
  // 使用 array_filter 函数去除每个数组中的空值
  return array_filter($value);
}, $array);

// 打印处理后的二维数组
print_r($array);

?>

Output result:

Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
            [3] => c
        )

    [1] => Array
        (
            [1] => d
            [2] => e
        )

    [2] => Array
        (
            [0] => f
            [2] => g
            [3] => h
            [4] => i
        )

)

In this example, we use the array_map function to traverse a two-dimensional array. In each loop, use the array_filter function to remove null values ​​in each subarray. Finally, the processed two-dimensional array is returned.

Both methods can achieve the operation of removing null values ​​in a two-dimensional array. Which method to use depends on specific needs and writing habits. In actual development, we can make choices based on code logic and efficiency.

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