Lecture 3 — Exercises


Solutions to the problems below must be sent to Submitty for grading. A separate file must submitted for each problem, as practiced in Lab 1. For these Lecture 3 exercises, you must submit your solutions before Wednesday, September 13 at 11:59:59. Starting with Lecture 4, you will be required to submit you lecture exercises within 24 hours of the end of lecture. Students are welcome to work on these problems in small groups, but each student should write the final version of their solutions independently to assure themselves that they understand.


  1. Which of the following are valid strings? Upload a text file to Submitty that contains just the variable names that are assigned to strings that are correct. For example if only the first two were correct your file would contain s0 on the first line and s1 on the second.

    >>> s0 = "Sheldon Cooper's apartment is in Pasedena"
    >>> s1 = 'This cheese shop's cheese is all gone"
    >>> s2 = """We are
    "The Knights of the Round Table"
    >>> s3 = "Toto, I said,\n"We aren't in Kansas, anymore!"
    >>> s4 = 'Have you seen the "Final Five"'s picture?'
    >>> s5 = "Have you seen the 'Final Five''s picture?"
  2. Submit a Python file that includes a single line of code that prints 25 '*' characters followed by 25 '+' characters, with no space in between. It must, of course, use the print function. The two characters must appear in your code much less than 25 times - at most three each!

  3. Write a program that assigns the value 4 to the variable x, the value 2 to the variable y and then uses exactly three print function calls to generate the output below (four lines, with the second line blank). The print calls must use the variables x and y rather than the values 4 and 2. The trick is to change the assignment of the sep and end parameters in the call to print. The character 4 is the first character on the 1st, 3rd and 4th lines of output.

4 2