How to Fix “Invalid Argument Supplied for foreach()” in PHP

🔥 Problem Example:
<?php
$data = null; // or could be a variable not set or not an array

foreach ($data as $item) { // Warning: Invalid argument supplied for foreach()
echo $item;
}
?>
❓ Why This Happens
The PHP warning:
E_WARNING: Invalid argument supplied for foreach()
means that the variable you're passing into foreach() is not iterable. This happens if the variable is:

null

a string

not defined

not an array or Traversable object

✅ Correct Code Example (Fix):
<?php
$data = ['apple', 'banana', 'orange']; // ✅ Valid array

foreach ($data as $item) {
echo $item . "<br>"; // ✅ Works perfectly
}
?>
🧠 Final Note from TopSourceCode:
✅ The “Invalid argument supplied for foreach()” warning in PHP is very common.
Always ensure that your variable is an array or iterable object before using foreach() to avoid this issue.