When working with PHP, is_iterable can help with a specific task: detects arrays and objects implementing Traversable.
This guide shows what is_iterable does, how to use it in code, and which details you should check before relying on the result.
What Is is_iterable in PHP?
Detects arrays and objects implementing Traversable.
Usage: The following examples show calls with suitable values. Consult the function parameters described in the examples, especially when optional arguments or extensions are involved.
Example 1: Basic Usage
The first example introduces is_iterable with a direct PHP expression.
<?php
var_dump(is_iterable([1, 2]));
Observe the value returned or printed by is_iterable and compare it with the input used in this example.
Example 2: A Different Input or Option
This second example demonstrates another input or condition, so you can compare the behavior with the first example.
<?php
var_dump(is_iterable((function () { yield 3; })()));
Observe the value returned or printed by is_iterable and compare it with the input used in this example.
Practical Example
Here is a small scenario illustrating how is_iterable can fit into application code. Run the example only in an appropriate development environment if it reads files, changes data, starts processes or connects to a service.
<?php
$source = new ArrayIterator(["A", "B"]); if (is_iterable($source)) foreach ($source as $entry) echo $entry;
Observe the value returned or printed by is_iterable and compare it with the input used in this example.
Important Behavior and Edge Cases
- Core behavior: Detects arrays and objects implementing Traversable.
- Important limitation: Countable and iterable are different contracts; not all iterables support count().
- Production use: Check return values and handle failures before acting on the result.
Comparison With Related Functions
| Function or Approach | Difference |
|---|---|
is_iterable() | Detects arrays and objects implementing Traversable. |
is_countable() | Related approach. Its purpose and return value differ; select it when your task matches that operation. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
Overlooking a special case of is_iterable(). | Countable and iterable are different contracts; not all iterables support count(). |
Using is_iterable() without checking the outcome. | Handle failures and confirm that the output is suitable for the next step. |
Key Takeaways
- Detects arrays and objects implementing Traversable.
- Countable and iterable are different contracts; not all iterables support count().
- Test the function with relevant inputs before using it in production.
Use is_iterable when its behavior matches the job you need to complete. For dependable results, consider the input data, returned value and limitations shown above.