my python study | Python Fiddle

import sys

a = 'Hello'
b = '你好' #have some problem with unicode
print a, len(a), a[0], a[-5]
print b, len(b)
c = 23
#this is wrong
#print a + c 
#should be like this
print a + str(c)

print "c / 2 =", c / 2, " || -c / 2 = ",-c / 2

def print_arg(arg):
    if arg == 'python' or arg == 'java' :
        arg = str(arg) + "!!!!"
    else:
    	arg = str(arg) + "???"
    print 'Hello,',str(arg).lower() % ('T.T') # % ('TT') is used to fill the %s holder.
    
    
if __name__ == '__main__':
    print_arg("Python \"du\" %s")  
    print sys.argv
#    print help(repr)
#print dir(sys) #see what sys module have(functions and paras)
#print help(sys.exit) #see the doc of this module's function.

print "###################string1#################################"
# 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/

# Basic string exercises
# Fill in the code for the functions below. main() is already set up
# to call the functions with a few different inputs,
# printing 'OK' when each function is correct.
# The starter code for each function includes a 'return'
# which is just a placeholder for your code.
# It's ok if you do not complete all the functions, and there
# are some additional functions to try in string2.py.

# A. donuts
# Given an int count of a number of donuts, return a string
# of the form 'Number of donuts: <count>', where <count> is the number
# passed in. However, if the count is 10 or more, then use the word 'many'
# instead of the actual count.
# So donuts(5) returns 'Number of donuts: 5'
# and donuts(23) returns 'Number of donuts: many'
def donuts(count):
	# +++your code here+++
	retStr = "Number of donuts: %s"
	if count < 10:
		retStr = retStr % (str(count))
	else:
		retStr = retStr % ('many')
	return retStr

# B. both_ends
# Given a string s, return a string made of the first 2
# and the last 2 chars of the original string,
# so 'spring' yields 'spng'. However, if the string length
# is less than 2, return instead the empty string.
def both_ends(s):
	# +++your code here+++
    if 2 > len(s):
    	return ''
    else:
    	first2 = s[:2]
    	last2 = s[-2:]
	return first2 + last2

# C. fix_start
# Given a string s, return a string
# where all occurences of its first char have
# been changed to '*', except do not change
# the first char itself.
# e.g. 'babble' yields 'ba**le'
# Assume that the string is length 1 or more.
# Hint: s.replace(stra, strb) returns a version of string s
# where all instances of stra have been replaced by strb.
def fix_start(s):
	# +++your code here+++
	return s[0]+s[1:].replace(s[0],'*')

# D. MixUp
# Given strings a and b, return a single string with a and b separated
# by a space '<a> <b>', except swap the first 2 chars of each string.
# e.g.
#   'mix', pod' -> 'pox mid'
#   'dog', 'dinner' -> 'dig donner'
# Assume a and b are length 2 or more.
def mix_up(a, b):
	# +++your code here+++
	return b[:2]+a[2:]+' '+a[:2]+b[2:]

# Provided simple 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))

# Provided main() calls the above functions with interesting inputs,
# using test() to check if each result is correct or not.
def main():
	print 'donuts'
	# Each line calls donuts, compares its result to the expected for that call.
	test(donuts(4), 'Number of donuts: 4')
	test(donuts(9), 'Number of donuts: 9')
  	test(donuts(10), 'Number of donuts: many')
	test(donuts(99), 'Number of donuts: many')

print
	print 'both_ends'
	test(both_ends('spring'), 'spng')
	test(both_ends('Hello'), 'Helo')
	test(both_ends('a'), '')
	test(both_ends('xyz'), 'xyyz')

print
	print 'fix_start'
	test(fix_start('babble'), 'ba**le')
	test(fix_start('aardvark'), 'a*rdv*rk')
	test(fix_start('google'), 'goo*le')
	test(fix_start('donut'), 'donut')

print
	print 'mix_up'
	test(mix_up('mix', 'pod'), 'pox mid')
	test(mix_up('dog', 'dinner'), 'dig donner')
	test(mix_up('gnash', 'sport'), 'spash gnort')
	test(mix_up('pezzy', 'firm'), 'fizzy perm')

# Standard boilerplate to call the main() function.
if __name__ == '__main__':
	main()
    
    
##########################################################################################
print "##############################string2################################################"
# 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 3 > len(s):
        return s
    else:
		if s[-3:] == 'ing':
			s = s + 'ly'
		else:
			s = s + 'ing'
		return s

# 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):
	# +++your code here+++
    notIndex = s.find('not')
    badIndex = s.find('bad')
    if -1 != notIndex and -1 != badIndex:
        if notIndex < badIndex:
            s = s[:notIndex] + 'good' + s[badIndex+len('bad'):]
    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):
	# +++your code here+++
	halveIndexA = len(a) / 2 #if len(a)=5 -len(a)/2 = -3 len(a)/2 = 2 ???
	halveIndexB = len(b) / 2
	return a[:-halveIndexA] + b[:-halveIndexB] + a[-halveIndexA:] + b[-halveIndexB:]

# 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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