《python基础教程》答案（第四章）

4.1

# created by swy"""solutions to beginning python"""def printTrueFalse(X):    if X:        print("%s is true" % str(X))    else:        print("%s is false" % str(X))printTrueFalse(0)printTrueFalse(1)printTrueFalse(2)printTrueFalse(3)printTrueFalse("abc")printTrueFalse("")

4.2

# created by swy"""solutions to beginning python"""def inRange(X):    if X in range(3, 9):        print("%s is in the range" % str(X))inRange(5)

4.3

# created by swy"""solutions to beginning python"""lookFor = "milk"lookIn = ["butter", "milk", "cheese"]if lookFor == lookIn[0]:    print("found it")elif lookFor == lookIn[1]:    print("found it ...")else:    print("did not find it")if lookFor in lookIn:    print("it is there")else:    print("it is not there")print(lookIn.index(lookFor))

4.4

# created by swy"""solutions to beginning python"""fridge = {
   "Milk": "Thise milk", "Cheese": "Emmentaler", "Butter": "Unsalted butter"}food_sought = "Butter"for foodKey in fridge:    print("\nlooking at : %s", foodKey)    if foodKey == food_sought:        print("key: %s \tValue: %s" % (foodKey, fridge[food_sought]))        breakelse:    print("it was not there")

4.5

# created by swy"""solutions to beginning python"""fridge = {
   "Milk": "Thise milk", "Cheese": "Emmentaler", "Butter": "Unsalted butter"}food_sought = "Butter"fridge_list = []for foodKey in fridge:    fridge_list.append(foodKey)print(fridge_list)while fridge_list:    if fridge_list.pop() == food_sought:        print("found it again")        break    else:        print("not found")

4.6

# created by swy"""solutions to beginning python"""fridge = {
   "Milk": "Thise milk", "Cheese": "Emmentaler", "Butter": "Unsalted butter"}food_sought = "Butter"try:    wrongKey = fridge["Beer"]except KeyError:    print("We are out of beer")try:    goodKey = fridge["Milk"]except KeyError:    print("We are out of Milk")