How to remove blank elements from php array

In PHP development, processing arrays is a very common operation. In practical applications, we often encounter situations where arrays contain blank elements. If these blank elements are not handled, the normal operation of the program may be affected. Therefore, this article will show you how to remove blank elements from an array using PHP.

1. What is a blank element

In PHP, we can create an array in the following way:

$arr = array('foo', '', 'bar');

The above code creates an array containing 3 elements, where The first element is 'foo', the second element is the empty string, and the third element is 'bar'. In actual development, there are many cases of such blank elements. For example, blank data may exist in form data submitted by users, or blank data may also appear in database query operations.

2. Use the array_filter() function to remove blank elements

PHP has many useful array functions built-in, including the array_filter() function. The array_filter() function is used to filter elements in an array according to specified conditions and return a new array. Typically, we use the callback function of the array_filter() function to filter array elements to remove blank elements.

The following is a sample code that uses the array_filter() function to remove blank elements in an array:

$arr = array('foo', '', 'bar');

// 定义回调函数
function filter_empty($var) {
    return trim($var) != '';
}

// 使用 array_filter() 函数去除空白元素
$arr = array_filter($arr, 'filter_empty');

// 输出新数组
print_r($arr);

Run the above code, the output result is:

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

As can be seen from the above code , use the array_filter() function to remove blank elements from the original array, and return a new array containing only non-empty elements.

In the above example code, we use a function named filter_empty as the callback function. This function uses the trim() function to remove spaces on both sides of the string, and then determines whether the string is an empty string. If it is not an empty string, it returns true, indicating that the element needs to be retained; otherwise, it returns false, indicating that the element needs to be filtered out.

3. Use foreach() to operate the array

In addition to using the array_filter() function, you can also use foreach() to loop through the array, and then use the unset() function to delete blank elements. The following is a sample code that uses foreach() loop to remove blank elements in the array:

$arr = array('foo', '', 'bar');

foreach ($arr as $i => $value) {
    if (trim($value) == '') {
        unset($arr[$i]);
    }
}

// 重新建立索引
$arr = array_values($arr);

// 输出新数组
print_r($arr);

Run the above code, the output result is:

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

In the above code, we use foreach() to loop through each element in the array. If the element is a blank element, that is, it is an empty string after calling the trim() function to remove the spaces on both sides, then use the unset() function to delete the element. Finally, we re-index the array using the array_values() function, resulting in a new array that does not contain blank elements.

4. Use the array_reduce() function to remove blank elements

In addition to the above two methods, you can also use the array_reduce() function to remove blank elements in the array. The array_reduce() function is used to iterate each element of the array, calculate all elements through the callback function, and return a single value.

The following is a sample code that uses the array_reduce() function to remove blank elements in an array:

$arr = array('foo', '', 'bar');

// 定义回调函数
function reduce_empty($carry, $item) {
    if (trim($item) != '') {
        $carry[] = $item;
    }
    return $carry;
}

// 使用 array_reduce() 函数去除空白元素
$arr = array_reduce($arr, 'reduce_empty', array());

// 输出新数组
print_r($arr);

Run the above code, the output result is:

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

In the above code, we A function called reduce_empty is defined that iterates over each element of the array. If the element is not a blank element, the element is added to a new array and the new array is returned. Finally, use the array_reduce() function to remove blank elements from the original array and return the new array.

5. Summary

This article introduces three methods of using PHP to remove blank elements in an array: using the array_filter() function, using the foreach() loop and using the array_reduce() function. Although these methods are different, they can all effectively remove blank elements in the array, thereby avoiding affecting the normal operation of the program. In actual development, we can choose the appropriate method to operate according to the actual situation.

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