Python(13)_if語句
阿新 • • 發佈:2018-12-23
epp for循環語句 不為 不包含 neapp ice extra code 代碼塊
# if 語句與for循環語句,這個模式在實際編程中經常用 cars = [‘audi‘,‘bmw‘,‘subaru‘,‘toyota‘] for car in cars: if car == ‘bmw‘: print(car.upper()) else: print(car.title())
程序2 :if語句
# if語句 age =7; if age>=18: print("You are old enough to vote!") # if與else if age>=18: print("You are old enough to vote!") else: print("Sorry,you are too young to vote.")
程序3 :使用多個elif代碼塊
# 使用多個elif代碼塊 age = 12 if age<4: price = 0 elif age<18: price = 5 elif age<65: price=10 else: price =5 print("Your admission cost is $"+str(price)+".")
程序:4:省略else代碼塊
‘‘‘else 是一條包羅萬象的語句,只要不滿足任何if 或elif 中的條件測試,其中的代碼就會執行,這可能會引入無效甚至惡意的數據。如果知道最終要測試的條件,應考慮使用 一個elif 代碼塊來代替else 僅當滿足相應的條件時,你的代碼才會執行。‘‘‘ # 省略else代碼塊 age = 98 if age<4: price = 0 elif age<18: price = 5 elif age<65: price=10 elif age>=65: price =5 print("Your admission cost is $"+str(price)+".")
程序6:if語句下嵌套for循環
‘‘‘在這裏,我們首先創建了一個空列表,其中不包含任何配料。在處我們進行了簡單檢查,而不是直接執行for 循環。在if 語句中將列表名用在條件表達式中 時,Python將在列表至少包含一個元素時返回True ,並在列表為空時返回False 。如果requested_toppings 不為空,就運行與前一個示例相同的for 循環;否則,就打印 一條消息,詢問顧客是否確實要點不加任何配料的普通比薩‘‘‘ requests =[] if requests: for request in requests: print("Adding "+request+".") print("\nFinished making your pizza") else: print("Are you sure you want a plain pizza")
程序7:多個列表,這種形式的在實際編碼中也常見
# 多個列表,這種形式的在實際編碼中也常見 available_toppings = {‘mushrooms‘,‘olives‘,‘green peppers‘,‘pepperoni‘,‘pineapple‘,‘extra cheese‘} requested_toppings = {‘mushrooms‘,‘french fries‘,‘extra cheese‘} for requested_topping in requested_toppings: if requested_topping in available_toppings: print("Adding "+requested_topping+".") else: print("Sorry,we don‘t have "+requested_topping) print("\nFinished making your pizza")
Python(13)_if語句