Invalid argument supplied for foreach()

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It often happens to me to handle data that can be either an array or a null variable and to feed some foreach with these data.

$values = get_values();

foreach ($values as $value){
  ...
}

When you feed a foreach with data that are not an array, you get a warning:

Warning: Invalid argument supplied for foreach() in [...]

Assuming it's not possible to refactor the get_values() function to always return an array (backward compatibility, not available source code, whatever other reason), I'm wondering which is the cleanest and most efficient way to avoid these warnings:

Casting $values to array
Initializing $values to array
Wrapping the foreach with an if
Other (please suggest)

Answers

Personally I find this to be the most clean - not sure if it's the most efficient, mind!

if (is_array($values) || is_object($values))
{
    foreach ($values as $value)
    {
        ...
    }
}

The reason for my preference is it doesn't allocate an empty array when you've got nothing to begin with anyway.

Monday, September 19, 2022

juananrey-563461600d58

Just modify this line

foreach ($query->result() as $row) {

foreach ((array)$query->result() as $row) {

Tuesday, September 20, 2022

johnnywho

You're looking for the array_slice function:

array_slice() returns the sequence of elements from the array array as specified by the offset...

$lines = file(...);
$lines = array_slice($lines, -50);

Thursday, October 13, 2022

alan

You should open and close your <rows/> in the books loop, and add a late check for odd books:

<?php 
$count = 0;
foreach ($contents as $content) 
{
    //var_dump($content);
    $books      = $content["tags"];
    $book_image = $content['content_image'];
    $book_desc  = $content['content_social_description'];


    foreach ($books as $book) 
    {
        ++$count;
        if($count == 1)
        {  
            echo "<div class='et_pb_row'>";
        }
        $book_name      = $book['tag_name'];
        $book_name_trim = str_replace(' ', '-', $book_name);
        ?>
        <!-- Inside the Book Loop -->
        <div class='et_pb_column et_pb_column_1_2 books' style="background: url('https://s3-us-west-2.amazonaws.com/crowdhubproverbs31/<?php echo $book_image ;?>');">
            <h2><?php echo $book_name; ?></h2>
            <p><?php echo $book_desc; ?></p>
            <?php echo $count; ?>
        </div>

        <?php
        if ($count == 2)
        {
            echo "</div>";
            $count = 0;
        }


    }
}

if ($count > 0)
{
    echo "</div>";
}
?>

Doing so, your $count variable will be incremented only when foreach($books AS $book) loop is run (thus you have at least one book to print)

Thursday, October 20, 2022

kjfletch

Foreach takes arrays and attributes each value of the array to the varname that you define. Invalid Argument simply means that the you did not provide a valid array.

For l.12, it simply means that you did not pass an array as the first arg to your function, which is due to your error line 88.

I would assume that your problem is that you haven't yet tried uploading a file and thus $_FILES is undefined. In my experience to use the $_FILES superglobal variable you usually have to upload a file via a form of enctype multi-part/formdata. To debug and check if it's defined do a var_dump or print_r on $_FILES before your foreach loop. As an added measure of security you might want to wrap said loop and your call to your mail_attachment function in an if (isset($_FILES))

Hope this helps

Tuesday, November 15, 2022

sawan

Change this:

$path[] = $dir;
foreach($path as $dirname){
    $add = glob($dirname . '/*.css');
    foreach($add as $file){

to this:

$path[] = $dir;
var_dump($path);
foreach($path as $dirname){
    $add = glob($dirname . '/*.css');
    var_dump($add);
    foreach($add as $file){

We don't know which line 131 is, so I don't know which foreach fails.

(I'm guessing the 2nd, because the first is practically forced to array by $path[] = ..)

Saturday, December 10, 2022

afri

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