Introduction to Iterators

An iterator is an object in Python that allows traversal over a collection of elements one value at a time.

It does not store all values explicitly for traversal. Instead, it produces the next value only when requested.

An iterator maintains its own internal state so it knows which element to return next.

Examples of iterator based objects include sequences like lists, tuples, strings, and files when accessed in an iterative manner.

Iterators exist to provide a standard and efficient way to access elements of a collection sequentially.

They solve several important problems They allow iteration without exposing internal structure They reduce memory usage by producing values lazily They support uniform iteration across different data types

Without iterators, Python would need separate logic for looping through each type of collection.

Iterators make looping consistent and predictable.

Iterators are used implicitly and explicitly across Python.

Common usage areas include for loops File reading line by line Data processing pipelines Custom data structures Generators and comprehensions

Whenever a for loop runs, Python internally uses an iterator.