CSc 7003, Programming for Data Science (Summer 2019)

Program 1 - Histogram of Letter Counts

Write a Python program that counts the number of occurrences of the alphabetical letters in a text file and plots a histogram as follows:

.

Here are couple of text files for you to test your program against:

lipogram

ra

Here is a program template:

import string
import sys
from graphics import *

def get_counts(fname):
# this function takes the name of a file as input parameter, fname
# it then reads the file into a string variable
# then proceeds to process the string for the count of letters
# answer should be returned in a list of 26 numbers

def draw(counts,win):
# this function takes as input the "counts" list and a
# graphic window, win. the function then proceeds to paint
# the histogram inside win

def main():
  win = GraphWin("Histogram Plot",1100,600)
  win.setBackground("white")
  counts = get_counts(sys.argv[1])
  #print(counts)
  draw(counts,win)
  p = win.getMouse()
  win.close()

main()

NOTES:

1. sys is a Python library that allows us to extract command line parameters. sys.argv[1] will contain the first command line parameter, sys.argv[2] the second and so on.
2. the Python commands to read from file into a string object is:

     with open(fname) as f:
       data = f.read().lower()
   

3. the string library contains useful functions such as

     string.ascii_lowercase returns a string "abcdefghijklmnopqrstuvwxyz"
   

4. Use the count(c) method to get the count of character c in a string
5. Graphics Package Documentation
6. Bar.py