Question

There are the map,reduce,filter functions to make list comprehensions.

What is the difference between passing a xrange argument or a range argument to each of these functions?
For example:

map(someFunc, range(1,11))

OR

map(someFunc,xrange(1,11))

Answer 1

In Python 2, range returns an actual list, while xrange returns a generating function which can be iterated over. Since map only cares that it iterates over a sequence, both are applicable, though xrange uses less memory. Python 3’s xrange replaces range, so your only option is to use range to return a generating function. (You can use [i for i in range(10)] to generate the actual range if so desired.)

The modulus operator returns 0, a falsey value, for the even numbers: 2 mod 2 is 0. As such, the even numbers are filtered out.