Assignment 2

Question #1

Consider the following simplified view of the visual spectrum of colors:
Infrared - red - yellow - green - blue - Ultraviolet

When a light source like a star is traveling sufficiently fast away from an observer, that star's light is red-shifted such that the perceived color is lower on the spectrum than the actual color emitted by the source, e.g., yellow goes to red, red goes to Infrared. Similarly, if a light source is traveling sufficiently fast towards an observer, that star's light is blue-shifted such that the perceived color is higher on the spectrum than the actual color emitted by the source, e.g., yellow goes to green, blue goes to Ultraviolet

Write and document a Python script convert.py which takes as command-line arguments a shift type in {red, blue} and the name of a single-column file of colors (one color per line) and outputs (1) for each color, the shifted color and, at the end, (2) the total number of shifts done as well as the total number of shifts into Infrared and Ultraviolet. Your script must work on datafile shift1.dat to produce the output given in typescript-file shift.script. You may assume that all colors in a given file are valid.

Question #2

Write and document a Python script stats1.py which takes as a command-line argument the name of a single-column file of real numbers (one real per line) and outputs the number, sum, minimum, mean, maximum, standard deviation, and variance of all reals in the file (see here for the mathematical formulas for computing the mean, standard deviation, and variance). Your script must work on datafiles stats1a.dat, stats1b.dat, stats1c.dat, and stats1d.dat to produce the output given in typescript-file stats1.script. You may assume that all reals are in the range -1000.0 to 1000.0 inclusive.

Hints

You may find the various example scripts in the course notes of use.

In Q2, you may find the math function sqrt() of use.

Submission

Please hand in printed copies of all of your Python script files. You must also submit these files electronically using the submit-assignment command. Note that each script file must have the following comment block at the top, where the X's are replaced with the appropriate information, followed by a docstring briefly describing the program in that script. For instance, my script for Question #1 of this assignment would begin with the following comment block:

#########################################################
##  CS 2500 (Fall 2009), Assignment #2, Question #1    ##
##   Script File Name: convert.py                      ##
##       Student Name: Todd Wareham                    ##
##         Login Name: harold                          ##
##              MUN #: 8008765                         ##
#########################################################

You do not have to develop your code on our CS departmental systems. However, as your code will be interpreted and tested on our CS departmental systems as part of the assignment marking process, you should ensure that your code interprets and runs correctly on at least one of these systems.

Additional Notes:

• August 19, 2:25pm
  Assignment #2 posted.

Created: August 19, 2009
Last Modified: August 19, 2009