How does __getitem__ enable sequence-like behavior in a class?

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__getitem__ to enable sequence-like behavior

The __getitem__ method enables sequence-like behavior in a Python class by allowing you to access items in the object using square bracket notation—just like you do with lists, tuples, or strings.

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✅ What it does:

When you define __getitem__(self, key) in your class:

• Python calls this method whenever you do obj[key]

• You can support:

  • Indexing (obj[0])

  • Slicing (obj[1:4])

  • Even complex keys like tuples (obj[1, 2])

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📦 Example:

python
class MySequence:
    def __init__(self, data):
        self.data = data

    def __getitem__(self, index):
        return self.data[index]

seq = MySequence([10, 20, 30, 40])
print(seq[1])      # 20
print(seq[1:3])    # [20, 30]

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🔁 What it enables:

• Looping with for item in obj

• Indexing and slicing

• Compatibility with len(), in, enumerate(), etc. (if other methods like __len__ and __iter__ are also defined)

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🧠 Summary:

Implementing __getitem__ turns your class into an indexable and iterable object, giving it familiar behavior like Python’s built-in sequences.

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