Python Mini-Course

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Day 4 Lesson 13Case study Word play

• Python Mini-Course
• University of Oklahoma
• Department of Psychology

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Lesson objectives

1. Read in values from a text file
2. Create useful functions for identifying patterns
   in text

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Files in Python

• Files are objects
• http//www.python.org/doc/2.5.2/lib/bltin-file-obj
  ects.html
• Use the open statement to instantiate a file
  object
• fin open('words.txt', 'r')
• print fin

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Files in Python

• File methods include
• f.readline()
• f.write()
• f.close()

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Reading a line

• fin open('words.txt', 'r')
• line fin.readline()
• print line
• line fin.readline()
• print word

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Reading a line

• word line.strip()
• print word
• word fin.readline().strip()
• print word
• fin.close()

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Iterating through the lines

• fin open('words.txt')
• for line in fin
• word line.strip()
• print word
• fin.close()

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Exercise 9.1

• Write a program that reads words.txt and prints
  only the words with more than 20 characters (not
  counting whitespace)

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Exercise 9.2

1. Write a function called has_no_e that returns
   True if the given word doesnt have the letter
   e in it.
2. Modify your program from the previous section to
   print only the words that have no e and compute
   the percentage of the words in the list have no
   e.

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Suggested exercises

• Any (or all) of the remaining Exercises from
  Chapters 8 and 9 of Think Python