How to remove null values ​​from an array in php

In PHP, sometimes we need to remove null values ​​​​in an array so that we can better process the data. This article will explore different ways to remove null values ​​from an array.

Method 1: Use the array_filter function

The array_filter() function is PHP’s built-in function for filtering array elements. When a callback function is passed, the function returns a function that only contains the return value of the callback function. A new array that is not FALSE (that is, not null, 0, " ", "0", false, array()). We can use this function to remove null values ​​​​in the array. The sample code is as follows:

$arr = array('foo', 0, '', null, false, 'bar', ' ', '0', array());
$arr = array_filter($arr); //过滤
print_r($arr); //只剩下 'foo'、'bar'

The result is as follows:

Array
(
    [0] => foo
    [5] => bar
)

Method 2: Use foreach loop to traverse the array

We also You can use a foreach loop to traverse the array and manually remove the null values. The sample code is as follows:

$arr = array('foo', 0, '', null, false, 'bar', ' ', '0', array());
foreach ($arr as $key => $value) {
    if (empty($value)) {
        unset($arr[$key]); //去除数组中的空值
    }
}
print_r($arr); //只剩下 'foo'、'bar'

The result is also:

Array
(
    [0] => foo
    [5] => bar
)

Method 3: Use the array_diff function

We also You can use the array_diff() function, which is used to return an array that contains all values ​​in the first parameter array but not in the remaining parameter arrays. In other words, we can put the null value into the second parameter. The sample code is as follows:

$arr = array('foo', 0, '', null, false, 'bar', ' ', '0', array());
$arr = array_diff($arr, array('')); //去除数组中的空值
print_r($arr); //只剩下 'foo'、'bar'

The result is also:

Array
(
    [0] => foo
    [5] => bar
)

In summary, we have many methods Null values ​​can be removed from PHP arrays, using the array_filter() function is the most convenient. However, if you need to manually process each element in the array, it may be better to use a foreach loop.

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