ITEC 380 2009fall ibarland

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hw09
Python finger exercises
moving trucks

Due Dec.11 23:59

Submit a python program with the following. (Practice good code, as always: Use named constants and helper functions/methods as appropriate; include comments giving the signature and purpose of each (non-anonymous) function.)

• (5pts) Create three Trucks. (You can represent trucks as objects, as three-tuples, or as a four-tuple where one field is simply the tag "truck".)
• (5pts) Write a function/method to move a truck. This can be a mutating method or not, as you prefer. Include two test cases.
• (15pts)

  Write a function which takes in a list of trucks and moves all of them using map or for; removes those that are off-screen using filter and lambda; and then adds one new truck to the list if there are fewer than some threshold.

  Include three to four test cases; print out the list before calling the function, and then again on the result / after calling the function. At least one test should call the function enough times so that all the initial trucks have left the scene.

  This should be a function which returns a new list; otherwise you couldn't easily use map or filter, since neither of those modify the input list.
  Extra credit (5pts): modify your list-function to be a procedure which mutates, instead. In order to have your changes seen by the caller, you'll need to be roundabout: have the caller “box” the real data into a list-of-length one, and have your procedure replace the first element of the (singleton) list it receives. Provide tests.

See the lecture notes for how to run python (either as a script, or interactively). You can import random, which will then let you call random.randrange(int).

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©2009, Ian Barland, Radford University Last modified 2009.Dec.06 (Sun)

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