9. Iterations and Loop Structures - 9 ITERATIONS AND LOOP...

Info icon This preview shows pages 1–6. Sign up to view the full content.

9. ITERATIONS AND LOOP STRUCTURES Rocky K. C. Chang October 18, 2015 (Adapted from John Zelle’s slides)
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Objectives To understand the concepts of definite and indefinite loops as they are realized in the Python for and while statements. To understand the programming patterns interactive loop and sentinel loop and their implementations using a Python while statement. To understand the programming pattern end-of-file loop and ways of implementing such loops in Python.
Image of page 2
For Loops: A Quick Review The for statement allows us to iterate through a sequence of values. for <var> in <sequence>: <body> The loop index variable var takes on each successive value in the sequence, and the statements in the body of the loop are executed once for each value.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Indefinite Loops The for loop is a definite loop, meaning that the number of iterations is determined when the loop starts. We can t use a definite loop unless we know the number of iterations ahead of time. The indefinite or conditional loop keeps iterating until certain conditions are met.
Image of page 4
Indefinite Loops while <condition>: <body> condition is a Boolean expression, just like in if statements. The body is a sequence of one or more statements.
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 6
This is the end of the preview. Sign up to access the rest of the document.
  • Fall '16
  • Rocky Chiang
  • loop, infile

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern