google python exercises | Python Fiddle

#!/usr/bin/python2.4 -tt
# Copyright 2010 Google Inc.
# Licensed under the Apache License, Version 2.0
# http://www.apache.org/licenses/LICENSE-2.0

# Google's Python Class
# http://code.google.com/edu/languages/google-python-class/

# Additional basic string exercises

# D. verbing
# Given a string, if its length is at least 3,
# add 'ing' to its end.
# Unless it already ends in 'ing', in which case
# add 'ly' instead.
# If the string length is less than 3, leave it unchanged.
# Return the resulting string.
def verbing(s):
  # +++your code here+++
  if len(s) < 3:
    return s
  else:
    if s[-3:] == "ing":
      return s + "ly"
    else:
      return s + "ing"

# E. not_bad
# Given a string, find the first appearance of the
# substring 'not' and 'bad'. If the 'bad' follows
# the 'not', replace the whole 'not'...'bad' substring
# with 'good'.
# Return the resulting string.
# So 'This dinner is not that bad!' yields:
# This dinner is good!
def not_bad(s):
    n = s.find('not')
    b = s.find('bad')
    if n != -1 and b != -1 and b > n:
        s = s[:n] + 'good' + s[b+3:]
        return s

# F. front_back
# Consider dividing a string into two halves.
# If the length is even, the front and back halves are the same length.
# If the length is odd, we'll say that the extra char goes in the front half.
# e.g. 'abcde', the front half is 'abc', the back half 'de'.
# Given 2 strings, a and b, return a string of the form
#  a-front + b-front + a-back + b-back
def front_back(a, b):
    if len(a) % 2 ==0 and len(b) == 0:
        a_half = len(a) / 2
        a_front = a[:a_half]
        a_back = a[a_half:]
        b_front = b[:b_half]
        b_back = b[b_half:]
        return a_front + b_front + a_back + b_back
    #Проверка 
	elif len(a) % 2 != 0:
        if len(b) % 2 == 0:
            b_half = len(b) / 2
            b_front = b[:b_half]
            b_back = b[b_half:]
            a_cel = len(a)//2
            a_half = len(a) - a_cel
            a_front = a[:a_half]
            a_back = a[a_half:]
            return a_front + b_front + a_back + b_back
        else:
            b_cel = len(b)//2
            b_half = len(b) - b_cel
            b_front = b[:b_half]
            b_back = b[b_half:]
            a_cel = len(a)//2
            a_half = len(a) - a_cel
            a_front = a[:a_half]
            a_back = a[a_half:]
            return a_front + b_front + a_back + b_back

else:
        if len(a) % 2 == 0:
            a_half = len(a) / 2
    		a_front = a[:a_half]
    		a_back = a[a_half:]
            b_cel = len(b)//2
    		b_half = len(b) - b_cel
    		b_front = b[:b_half]
    		b_back = b[b_half:]
            return a_front + b_front + a_back + b_back
  		else:
            a_cel = len(a)//2
    		a_half = len(a) - a_cel
    		a_front = a[:a_half]
    		a_back = a[a_half:]
            b_cel = len(b)//2
    		b_half = len(b) - b_cel
    		b_front = b[:b_half]
    		b_back = b[b_half:]
			return a_front + b_front + a_back + b_back

# Simple provided test() function used in main() to print
# what each function returns vs. what it's supposed to return.
def test(got, expected):
  if got == expected:
    prefix = ' OK '
  else:
    prefix = '  X '
  print '%s got: %s expected: %s' % (prefix, repr(got), repr(expected))

# main() calls the above functions with interesting inputs,
# using the above test() to check if the result is correct or not.
def main():
  print 'verbing'
  test(verbing('hail'), 'hailing')
  test(verbing('swiming'), 'swimingly')
  test(verbing('do'), 'do')

print
  print 'not_bad'
  test(not_bad('This movie is not so bad'), 'This movie is good')
  test(not_bad('This dinner is not that bad!'), 'This dinner is good!')
  test(not_bad('This tea is not hot'), 'This tea is not hot')
  test(not_bad("It's bad yet not"), "It's bad yet not")

print
  print 'front_back'
  test(front_back('abcd', 'xy'), 'abxcdy')
  test(front_back('abcde', 'xyz'), 'abcxydez')
  test(front_back('Kitten', 'Donut'), 'KitDontenut')

if __name__ == '__main__':
  main()

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