Concept: range()

The range function is a built-in Python function that generates a sequence of numbers. It is commonly used in for loops to iterate over a specific range of values. The range() function can take one, two, or three arguments:

When called with a single argument, it generates numbers from $0$ up to (but not including) the specified value.

for i in range(5):
    print(i, end=" ")
# Output: 0 1 2 3 4

When called with two arguments, it generates numbers from the first argument up to (but not including) the second argument.

for i in range(1, 5):
    print(i, end=" ")
# Output: 1 2 3 4

When called with three arguments, it generates numbers from the first argument up to (but not including) the second argument, incrementing by the third argument.

for i in range(1, 5, 2):
    print(i, end=" ")
# Output: 1 3

While the examples above used positive argmument, the range() function can also accept negative arguments, allowing for reverse iteration.

for i in range(5, 0, -1):
    print(i, end=" ")
# Output: 5 4 3 2 1