What is the difference between range and xrange ? How has this changed over time?

The difference between range() and xrange() in Python primarily revolves around memory usage and performance, particularly in different versions of Python.

Python 2: range() vs xrange()

In Python 2, range() and xrange() are both used to generate a sequence of numbers, but they do so in different ways:

• range() generates a list of all the numbers in the specified range and stores them in memory. This can lead to significant memory usage, especially for large ranges[1][3][4][5][9].
• xrange(), on the other hand, generates the numbers on demand (lazy evaluation) and returns an xrange object. It does not store the entire list in memory, making it more memory-efficient. This is particularly useful for large ranges or when iterating over the numbers generated is done only once[1][3][4][5][9].

Python 3: Changes in range()

With the transition to Python 3, xrange() was removed and range() was redesigned to behave more like xrange() from Python 2. In Python 3, range() now:

• Returns a range object that generates the numbers on demand, similar to the xrange() object in Python 2. This change means that range() in Python 3 is more memory-efficient than range() in Python 2, as it does not generate a static list at runtime[2][5][6][10].

Performance Considerations

• Memory Usage: As mentioned, xrange() (Python 2) and range() (Python 3) are more memory-efficient as they generate numbers on demand and do not store the entire list in memory[1][3][4][5].
• Speed: When iterating over the same sequence multiple times, range() in Python 2 might perform better since it does not need to regenerate the integer objects. However, for a single iteration, especially over large ranges, xrange() is generally faster due to its on-demand generation of n...