How can you make an object iterable in Python?

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Make an object iterable

To make an object iterable in Python, you need to implement either:

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✅ Option 1: __iter__()

The simplest and most common way is to define an __iter__() method that returns an iterator (usually self or a generator).

Example:

python
class MyIterable:
    def __init__(self, data):
        self.data = data
    
    def __iter__(self):
        return iter(self.data)  # delegates to the iterable data

obj = MyIterable([1, 2, 3])
for item in obj:
    print(item)

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✅ Option 2: __getitem__() (legacy approach)

If your object implements __getitem__() and raises IndexError when the sequence ends, it is implicitly iterable.

Example:

python
class MyIterable:
    def __init__(self, data):
        self.data = data
    
    def __getitem__(self, index):
        return self.data[index]

obj = MyIterable([10, 20, 30])
for item in obj:
    print(item)

Python internally tries to call obj[0], obj[1], ... until IndexError is raised.

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🧠 Summary:

Method	Required?	Purpose
__iter__()	Yes	Returns an iterator for your object
__next__()	Optional	Needed if your class is also the iterator
__getitem__()	Legacy	Allows iteration without __iter__()

✅ Best practice: Prefer __iter__() + generators for clean, efficient code.

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