Highlights from this chapter include:
- A
whileloop runs a set of statements, known as the loop body, while a given condition, known as the loop expression, is true. - A
forloop can be used to iterate over elements of a container object. - A
range()function generates a sequence of integers between the two numbers given a step size. - A nested loop has one or more loops within the body of another loop.
- A
breakstatement is used within aforor awhileloop to allow the program execution to exit the loop once a given condition is triggered. - A
continuestatement allows for skipping the execution of the remainder of the loop without exiting the loop entirely. - A loop
elsestatement runs after the loop's execution is completed without being interrupted by abreakstatement.
At this point, you should be able to write programs with loop constructs. The programming practice below ties together most topics presented in the chapter.
| Function | Description |
|---|---|
|
Generates a sequence beginning at 0 until endwith step size of 1. |
|
Generates a sequence beginning at |
|
Generates a sequence beginning at |
| Loop constructs | Description |
|
# initialization
while expression:
# loop body
# statements after the loop |
|
# initialization
for loop_variable in container:
# loop body
# statements after the loop |
Nested |
while outer_loop_expression:
# outer loop body (1)
while inner_loop_expression:
# inner loop body
# outer loop body (2)
# statements after the loop |
|
# initialization
while loop_expression:
# loop body
if break_condition:
break
# remaining body of loop
# statements after the loop |
|
# initialization
while loop_expression:
# loop body
if continue_condition:
continue
# remaining body of loop
# statements after the loop |
Loop |
# initialization
for loop_expression:
# loop body
if break_condition:
break
# remaining body of loop
else:
# loop else statement
# statements after the loop |
Try It
Prime numbers
Write a program that takes in a positive integer number (N) and prints out the first N prime numbers on separate lines.
Note: A prime number is a number that is not divisible by any positive number larger than 1. To check whether a number is prime, the condition of number % i != 0 can be checked for i greater than 1 and less than number.
Ex: if N = 6, the output is:
2
3
5
7
11
13