All Units Loops

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1. Looping with different step sizes
   1. The Range Function
   2. Step Size
   3. Looping Backwards

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Looping with different step sizes

The Range Function

range(start, stop, [step])

• start: Number to start range at (inclusive), default: 0
• stop: Number to end range before (exclusive)
• step: The gap between each number in the range, default: 1

The range() function only accepts integers, or whole numbers, so floating numbers, or numbers with decimals will cause this error message:

TypeError: 'float' object cannot be interpreted as an integer

Step Size

The term increment means to add. You can change the incrementation of a loop with the step parameter.

Code

# Count by fifty
for number in range(100, 350, 50):
    print(number)

Output

100
150
200
250
300

Looping Backwards

Step size can also be negative, in case you want to loop backwards. This is called decrementing the loop counter.

Code

for i in range(3, 0, -1):
    print(str(i) + "...")
print("Blast off!")

The line to print "Blast off!" is at the same indentation level as the start of the loop. This means that it is not part of the loop body and will only run once, after the loop finishes.

Output

3...
2...
1...
Blast off!

Note: If stop is less than start and step is not set to a negative value, the range will be empty.

backwards = list(range(3, 0))
print(backwards)
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