PHP determines whether a multidimensional array is empty

PHP is one of the most commonly used Web programming languages ​​today. When we develop a website or web application, we often need to use arrays to store data. Arrays are a very commonly used data structure, and we can even use multi-dimensional arrays to store more complex data. When dealing with multi-dimensional arrays, sometimes we need to determine whether it is empty. This article will introduce several common methods for reference.

1. Determine whether a multi-dimensional array is empty through the count() function

The count() function is one of the most commonly used functions in PHP. It can be used to count the number of elements in an array. When determining whether a multidimensional array is empty, you can use the count() function to determine whether the number of elements is 0. If it is 0, the array is empty. The sample code is as follows:

function multi_array_empty($array){
    if(is_array($array)){
        foreach($array as $value){
            if(!multi_array_empty($value)){
                return false;
            }
        }
    }else{
        if(!empty($array)){
            return false;
        }
    }
    return true;
}

2. Determine whether the multi-dimensional array is empty through the empty() function

The empty() function can also be used to determine whether the array is empty. It can determine whether any value is empty, including strings, numbers, Boolean values, objects, and arrays. When determining whether a multidimensional array is empty, you can use the empty() function to determine whether its first element is empty. If it is empty, the array is empty. The sample code is as follows:

function multi_array_empty($array){
    if(is_array($array)){
        foreach($array as $value){
            if(!multi_array_empty($value)){
                return false;
            }
        }
        if(empty($array)){
            return true;
        }
    }else{
        if(empty($array)){
            return true;
        }
    }
    return false;
}

3. Determine whether the multi-dimensional array is empty through the array_filter() function

The array_filter() function can filter the elements in the array and return a new array. While filtering, if the array is empty, false is returned. We can use this feature to determine whether a multidimensional array is empty. The sample code is as follows:

function multi_array_empty($array){
    if(is_array($array)){
        $flag = true;
        foreach($array as $value){
            if(!multi_array_empty($value)){
                $flag = false;
            }
        }
        return array_filter($array) == false && $flag;
    }else{
        return empty($array);
    }
}

4. Determine whether a multi-dimensional array is empty through recursive traversal

Recursive traversal is also a method to determine whether a multi-dimensional array is empty. We can use a recursive function to iterate through all elements in a multidimensional array and determine whether they are empty. The sample code is as follows:

function multi_array_empty($array){
    $flag = true;
    foreach($array as $value){
        if(is_array($value)){
            $flag &= multi_array_empty($value);
        }else{
            $flag &= empty($value);
        }
    }
    return $flag;
}

In summary, this article introduces four common methods to determine whether a multi-dimensional array is empty, namely: through the count() function, empty() function, array_filter() function and recursion Traverse. When using, you can choose different judgment methods according to actual needs.

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