Iterating by Counting

• A common task in programming
• Used with loops
  • iterate a specified number of times
  • accessing indexes
  • creating a sequence of numbers

# initialize counter
i=0

# Loop until counter reaches 10
while i < 10:
    print(i, end='')
    # single quote replaces the default of new lines 
    # => output in one line

    # Increment counter
    i = i+1

What is a Range?

• Generated, immutable sequence (string and tubple) of integers
• Inherits sequence functions, methods and operators

range(stop)
# genrates a range of integers starting with 0 and ending with stop(exclusive)

Range examples

# Iterate through numbers from 0 to 9
for i in range(10):
    # no need to initialize (i) since
    # when you use a for loop with the range(), the loop automatically initializes the loop variable (i) for you.
    print(i, end=' ')
# Output

Range function

range(start, stop, step=1)
# generates a range of intefers stareting with staert and ending with stop(explusive), step is an optional and defaults to 1

Range Step Example

r = range(20, 50, 5)
print(r)
# Output
range(20, 50, 5)

# convert it to a list
r = range(20, 50, 5)
print(list(r))
# Output
[20,25,30,35,40,45]

Negative Range Example

r = range(10,0)
print(list(r))