How Does Python's `range()` Function Achieve Near-Constant Time Containment Checks?

Unveiling the Secrets of Python's Lightning-Fast "range()" Function

contrary to popular belief, Python 3's range() function is not a generator that produces numbers on demand. Rather, it is a full-fledged sequence object that stores start, stop, and step values. Astonishingly, this clever object enables it to determine if a given number falls within its range in near-constant time.

The range() object leverages its containment hook, __contains__, to calculate numerically whether a number belongs to its range. This lightning-fast operation eliminates the need to iterate through a potentially vast number of integers, resulting in instantaneous performance.

As the range() object documentation aptly states, its优势 lies in its memory footprint. Unlike conventional lists or tuples, it consumes a negligible amount of memory, regardless of the range's size. This remarkable efficiency stems from the fact that it calculates individual items and subranges only when needed.

In essence, the range() object is an agile sequence object that provides superfast containment checks without incurring the overhead of generating a full list of integers. This design philosophy empowers Python programmers to efficiently handle numerical ranges, a cornerstone of many programming tasks.

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