PHP Iterables

by CodeCapsule

🔁 PHP Iterables

In PHP, iterable means anything that can be looped using foreach.

PHP introduced the iterable type (PHP 7.1+) to accept:

✔ Arrays
✔ Traversable Objects (Iterator, Generator, etc.)

If a variable can be used in foreach, PHP calls it iterable.

1️⃣ What is an Iterable?

Any of the following:

✔ Array

✔ Object implementing Traversable

✔ Generator

All these can be used with foreach.
Therefore, they are iterables.

2️⃣ Using `iterable` as a Type Hint

You can define a function that accepts any iterable:

Works with both arrays & generators:

3️⃣ Returning an Iterable

4️⃣ Iterable with Generators (Very Important)

Generators allow you to create lazy-loaded, memory-efficient iterables.

Output:

5️⃣ Iterable with Objects (Iterator Interface)

class MyList implements Iterator {
private $items = ["a", "b", "c"];
private $index = 0;

public function current() { return $this->items[$this->index]; }
public function key() { return $this->index; }
public function next() { $this->index++; }
public function rewind() { $this->index = 0; }
public function valid() { return isset($this->items[$this->index]); }
}

$list = new MyList();

foreach ($list as $value) {
echo $value . " ";
}

class MyList implements Iterator {

private $items = ["a", "b", "c"];

private $index = 0;

public function current() { return $this->items[$this->index]; }

public function key() { return $this->index; }

public function next() { $this->index++; }

public function rewind() { $this->index = 0; }

public function valid() { return isset($this->items[$this->index]); }

}

$list = new MyList();

foreach ($list as $value) {

echo $value . " ";

}

6️⃣ Why Use Iterable Type?

✔ Accepts both arrays + Traversable objects
✔ More flexible than array type
✔ Used in modern PHP libraries
✔ Useful for dependency injection
✔ Great for reading large files with generators
✔ Helps make functions truly generic

7️⃣ Checking if Something is Iterable

🎯 Summary (Easy to Remember)

Concept	Meaning
iterable	Anything you can loop using `foreach`
Accepts	Arrays + Traversable (Generators, Iterators)
Type hint	`function test(iterable $x)`
Return type	`: iterable`
Check	`is_iterable()`

PHP Iterables

🔁 PHP Iterables

1️⃣ What is an Iterable?

✔ Array

✔ Object implementing Traversable

✔ Generator

2️⃣ Using `iterable` as a Type Hint

3️⃣ Returning an Iterable

4️⃣ Iterable with Generators (Very Important)

5️⃣ Iterable with Objects (Iterator Interface)

6️⃣ Why Use Iterable Type?

7️⃣ Checking if Something is Iterable

🎯 Summary (Easy to Remember)

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PHP Iterables

🔁 PHP Iterables

1️⃣ What is an Iterable?

✔ Array

✔ Object implementing Traversable

✔ Generator

2️⃣ Using iterable as a Type Hint

3️⃣ Returning an Iterable

4️⃣ Iterable with Generators (Very Important)

5️⃣ Iterable with Objects (Iterator Interface)

6️⃣ Why Use Iterable Type?

7️⃣ Checking if Something is Iterable

🎯 Summary (Easy to Remember)

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2️⃣ Using `iterable` as a Type Hint