for-loops.md

For Loops

For loops are a way to "iterate" over a known range of values.

Terms

Term	Meaning
Loop	A method to repeat operation(s) multiple times
Iterate	To perform an action repeatedly
Range	The possible values used, with a minimum and maximum value

Pseudocode

for count is from 0 to 9:
    display count

Note:

• 0 to 10 is a range of values

Flowchart

Code

for count in range(10):
    print(count)

Note:

• the range() function always counts to one less than the maximum
• range() has general structure range(minimum, maximum, increment)

Output

0
1
2
3
4
5
6
7
8
9

Range Function

Examples of values generated by range():

Options	Example	Values
range(maximum)	range(5)	0, 1, 2, 3, 4
range(minimum, maximum)	range(1, 5)	1, 2, 3, 4
range(minimum, maximum, step)	range(1, 5, 2)	1, 3

Example 1

This example goes from 1 to 9, in increments of 3.

As 7 + 3 is greater than 9, the loop stops after displaying 7.

Pseudocode

for count is from 1 to 10 step 3:
    display count

Python

for count in range(1, 10, 3):
    print(count)

Output

1
4
7