What is a generator in Python?

A generator in Python is a specific type of function that uses the yield statement to produce a series of values one at a time and only when requested. This approach allows generators to generate values "on the fly," meaning they do not compute all the values at once or store them in memory. Instead, they provide an elegant way to iterate through data without the overhead of creating and storing the entire dataset at once, which is particularly beneficial for managing large datasets or streams of data.

By yielding values, a generator maintains its state between successive calls, allowing it to resume where it left off, thus making it more memory-efficient and suitable for certain applications, such as lazy evaluation and infinite sequences. This functional characteristic sets generators apart from regular functions and other constructs designed to return collections of values, such as lists or tuples.