Python 101 - Lesson 5 - Chapter 7

# Exercise 7.1
# Write a program to read through a file
# and print the contents of the file (line by
# line) all in upper case. Executing the
# program will look as follows.

fname = raw_input('Enter a file name:')

try:
  fhandle = open(fname)
except:
  print 'The file name(',fname,') you entered is wrong, try again.'
  exit()

for line in fhandle:
  print line.rstrip().upper()

fhandle.close()

# Exercise 7.2
# Write a program to prompt for a file name
# an then read through the file and look
# for lines of the form: X-DSPAM-Confidence: 0.8475
# When you encounter a line that starts with
# "X-DSPAM-Confidence:" pull apart the line to
# extract the floating point number on the line.
# Count these lines and the compute the total of
# the spam confidence values from these lines. When
# you reach the end of the file, print out the
# average spam confidence.

fname = raw_input('Enter the file name:')

try:
  fhandle = open(fname)
except:
  print 'The file name(',fname,') you entered is wrong, try again.'
  exit()

count = 0
total = 0

for line in fhandle:
  line = line.rstrip()
  linesinuse = line.startswith('X-DSPAM-Confidence:')
  if linesinuse:
    count += 1
    keep = line[20:]
    total += float(keep)

div = float(total / count)

print 'Average spam confidence:',div

# Exercise 7.3
# Sometimes when programmers get bored or want to
# have a bit of fun, they add a harmless Easter Egg to
# their program (en.wikipedia.org/wiki/Easter_egg_(media)).
# Modify the program that prompts the user for the file
# name so that it prints a funny message when the user
# types in the exact file name ’na na boo boo’.
# The program should behave normally for all other
# files which exist and don’t exist. Here is a
# sample execution of the program:

fname = raw_input('Enter the file name:')


try:
  fhandle = open(fname)
except:
  if fname == "na na boo boo":
    print 'NA NA BOO BOO TO YOU - You have been punk\'d!'
  else:
    print 'The file name(',fname,') you entered is wrong, try again.'
  exit()


count = 0
total = 0

for line in fhandle:
  line = line.rstrip()
  linesinuse = line.startswith('X-DSPAM-Confidence:')
  if linesinuse:
    count += 1
    keep = line[20:]
    total += float(keep)

div = float(total / count)

print 'Average spam confidence:',div