range

So what does range really return?

Instead of returning the list of numbers (as it used to do in Python 2), now it returns a range object that provides "the opportunity to go over the specific series of numbers" without actually creating the list of numbers. Getting an object instead of the whole list has a number of advantages. One is space in the memory. In a later example we'll see how much memory is needed for the object returned by the range function and how much would it take to have the corresponding list of numbers in memory. For now let's see how we can use it. range can have 1, 2, or 3 parameters.

• range(start, end, step) - Go from start (included) to end (not included) every step value.
• range(start, end) - Where step defaults to 1.
• range(end) - Where start defaults to 0, step defaults to 1.

range with 3 parameters

Go from start (included) to end (not included) every step value.

rng = range(3, 11, 2)

print(rng)
print()

for num in rng:
    print(num)

Output:

range(3, 11, 2)

3
5
7
9

range with 2 parameters

Go from start (included) to end (not included) every step=1.

rng = range(3, 7)

for num in rng:
    print(num)

Output:

3
4
5
6

range with 1 parameter

Go from start=0 (included) to end (not included) every step=1.

rng = range(3)

for num in rng:
    print(num)

Output:

0
1
2