Go through array and check if a field is empty (PHP)

Question

In one of the files I have a dynamic table that receives data from BD, but with the possibility of inserting more rows in the table. Note that when inserting more rows the idFaturacao will be empty.

This is my table:

<TABLE id="dataTable">
<?php 
    $query_periodosFaturacao = mysqli_query($link,"SELECT * FROM faturacao WHERE fk_obras=$id ORDER BY num_fatura ASC");
    while($periodosFaturacao = mysqli_fetch_array($query_periodosFaturacao)) {
            echo "<TR>";
            echo "<TD width='100px;'><INPUT type='date' id='data_afaturar' name='data_afaturar[]' value='".$periodosFaturacao['data']."' required/></TD>";
            echo "<TD><input type='text' name='valor_afaturar[]' id='valor_afaturar' value='".$periodosFaturacao['valor']."' required>€</TD>";
            echo "<input type='hidden' name='idFaturacao[]' value='".$periodosFaturacao['id']."' />";
            echo "</TR>";
    }
    ?>
</TABLE>

In another file where I send the data to the database, the problem is here! array, the elements that are empty it makes the INSERT and the elements in which idFaturacao is filled it does the UPDATE info. I don’t know how to check the empty and filled elements in the array.

$data_afaturar = $_POST['data_afaturar'];
$valor_afaturar = $_POST['valor_afaturar'];
$idFaturacao = $_POST['idFaturacao'];

foreach($data_afaturar as $a => $b){
    if(empty($idFaturacao[$a])){
        echo "INSERT";
    }
    else{
        echo "UPDATE";
    }
}

Thank you for your attention!

Answer 1

Por exemplo, se o array for assim :'1', '2', '', '4'. Just check if $b is empty

Test by clicking here

$idFaturacao = array("1", "2", "", "4");

foreach ($idFaturacao as $a => $b) {
    //$b = trim($b);
    if (empty($b))
        echo "indice $a -> $b faz INSERT <br>";
    else
        echo "indice $a -> $b faz UPDATE <br>";
}

With question code test here

$data_afaturar = array("a", "b", "c", "d");
$idFaturacao = array("1", "2", "", "4");


foreach($data_afaturar as $a => $b){
    if(empty($idFaturacao[$a])){
        echo "indice $a -> $b faz INSERT <br>";
    }
    else{
        echo "indice $a -> $b faz UPDATE <br>";
    }
}