How to check if a multidimensional array is empty or not?

Question

Basically, I have a multidimensional array, and I need to check whether or not it is simply empty, or not.

I currently have an if statement trying to do this with:

if(!empty($csv_array)) 
{   
    //My code goes here if the array is not empty
}

Although, that if statement is being activated whether the multidimensional array is empty or not.

This is what the array looks like when empty:

Array
(
    [0] => Array
        (
        )

)

This is what the array looks like when it has a few elements in it:

Array
(
    [0] => Array
        (
        )

    [1] => Array
        (
            [1] => question1
            [2] => answer1
            [3] => answer2
            [4] => answer3
            [5] => answer4
        )

    [2] => Array
        (
            [1] => question2
            [2] => answer1
            [3] => answer2
            [4] => answer3
            [5] => answer4
        )

    [3] => Array
        (
            [1] => question3
            [2] => answer1
            [3] => answer2
            [4] => answer3
            [5] => answer4
        )

)

My array elements always start at 1, and not 0. Long story why, and no point explaining since it is off-topic to this question.

If needed, this is the code that is creating the array. It is being pulled from an uploaded CSV file.

$csv_array = array(array());
if (!empty($_FILES['upload_csv']['tmp_name'])) 
{
    $file = fopen($_FILES['upload_csv']['tmp_name'], 'r');
}

if($file)
{
    while (($line = fgetcsv($file)) !== FALSE) 
    {
        $csv_array[] = array_combine(range(1, count($line)), array_values($line));
    }

    fclose($file);
}

So in conclusion, I need to modify my if statement to check whether the array is empty or not.

Thanks in advance!

Answer 1

So simply check for if the first key is present in array or not.

Example

if(!isset($csv_array[1])) 
{   
    //My code goes here if the array is not empty
}

Answer 2

Considering a data payload of indeterminant depth, here are a few performant approaches.

1. Short circuit the closure of array_walk_recursive() by catching a thrown exception upon encountering a leafnode. Demo

   function hasNonEmptyArray(array $array): bool
   {
       try {
           array_walk_recursive(
               $array,
               fn($v, $k) => throw new Exception("Found element $k\n")
           );
           return false;
       } catch (Exception $e) {
           echo $e->getMessage();
           return true;
       }
   }
   

2. Return early from a foreach() while looping the leaf nodes of a Recursive Iterator. Demo

   function hasNonEmptyArray(array $array): bool
   {
       $iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($array));
       foreach ($iterator as $k => $v) {
           echo "Found element $k\n";
           return true;
       }
       return false;
   }
   

3. Implement a userland recursive function to return true as soon as a leaf node is encountered. Demo

   function hasNonEmptyArray(array $array): bool
   {
       foreach ($array as $k => $v) {
           if (is_array($v)) {
               if (hasNonEmptyArray($v)) {
                   return true;  // pass deeper true outcome up the call chain
               }
           } else {
               echo "Found element $k\n";
               return true;
           }
       }
       return false;
   }
   

---

_{As for a lame answer which will not be terribly useful for future readers but will work for the asked question's context, just use if (!empty($csv_array[1])) { because checking if key 1 exists and has a non-falsey value will be enough.}

Answer 3

You could possibly use an all rounder recursive function to check if any of the nested arrays are truthy.

Implementation would look like this:

function array_is_all_empty(array $array): bool
{
    foreach ($array as $value) {
        if (is_array($value) && !array_is_all_empty($value)) {
            return false;
        }

        if (!is_array($value) && !empty($value)) {
            return false;
        }
    }

    return true;
}

This will return true if the nested array is fully empty.

Answer 4

Combine array_filter() and array_map() for result. ( Result Test )

<?php
    $arrayData = [
        '0'=> [],
        '1'=> [
            'question1',
            'answer1',
            'answer2',
            'answer3',
            'answer4'
        ],
        '2'=> [
            'question1',
            'answer1',
            'answer2',
            'answer3',
            'answer4'
        ]
    ];

    $arrayEmpty = [
        '0' => [],
        '1' => [
            '1' => '',
            '2' => '',
            '3' => ''
        ]
    ];

    $resultData = array_filter(array_map('array_filter', $arrayData));
    $resultEmpty = array_filter(array_map('array_filter', $arrayEmpty));

    var_dump('Data', empty($resultData));
    var_dump('Empty', empty($resultEmpty));

Answer 5

If you don't know the structure of the multidimensional array

public function isEmpty(array $array): bool
{
    $empty = true;

    array_walk_recursive($array, function ($leaf) use (&$empty) {
        if ($leaf === [] || $leaf === '') {
            return;
        }

        $empty = false;
    });

    return $empty;
}

Just keep in mind all leaf nodes will be parsed.

Answer 6

You can filter the array, by default this will remove all empty values. Then you can just check if it's empty:

$filtered = array_filter($csv_array);
if (!empty($filtered)) {
  // your code
}

Note: This will work with the code posted in your question, if you added another dimension to one of the arrays which was empty, it wouldn't:

$array = array(array()); // empty($filtered) = true;
$array = array(array(array())); // empty($filtered) = false;

Answer 7

just to be on the save side you want it to remove the empty lines ? or do you want to return if any array is empty ? or do you need a list which positions are empty ?

this is just a thought and !!! not tested !!!

/**
 * multi array scan 
 * 
 * @param $array array
 * 
 * @return bool
 */
function scan_array($array = array()){
  if (empty($array)) return true;

  foreach ($array as $sarray) {
    if (empty($sarray)) return true;
  } 

  return false;
}

Answer 8

You can use array_push to avoid this situation,

$result_array = array();

array_push($result_array,$new_array);

refer array_push

Then you can check it using if (!empty($result_array)) { }