[Python基础] 2-笨办法学Python3小结II

34.访问列表元素

小结：这节主要讲了列表基数（从0开始）与序数（从1开始）的区别

练习：

animals = ["bear", "python3.6", "peacock", "kangaroo", "whale", "platypus"]

print("位置为1的动物是第二只动物,是python3.6", animals[1])
print("第三只动物位置为2的动物,是peacock", animals[2])
print("第一只动物位置为0的动物,是bear", animals[0])
print("位置为3的动物是第四只动物,是kangaroo", animals[3])
print("第五只动物位置为4的动物,是whale", animals[4])
print("位置为3的动物是第四只动物,是kangaroo", animals[3])
print("第六只动物位置为5的动物,是platypus", animals[5])
print("位置为4的动物是第五只动物,是whale", animals[4])

35.分支与函数

小结：这节主要讲了if语句，函数的混用，并以一个游戏的形式呈现，使用while True可以写一个无限循环

练习：

from sys import exit  #从sys模块中导入exit函数

def gold_room(): 
    print("This room is full of gold. How much do you take?")
    choice = input("> ")

    if "0" in choice or "1" in choice:
        how_much = int(choice)
    else:
        dead("Man, learn to type a number.")

    if how_much < 50:
        print("Nice, you're not greedy, you win!")
        exit(0)
    else:
        dead("You greedy bastard!")


def bear_room():
    print("There is a bear here.")
    print("The bear has a bunck of honey.")
    print("The fat bear is in front of another door.")
    print("How are you going to move the bear?")
    bear_moved = False  #默认熊没有走开

    while True:  #创建一个无限循环
        choice = input("> ")

        if choice == "take honey": 
            dead("The bear looks at you then slaps your face off.")
        elif choice == "taunt bear" and not bear_moved:  
            print("The bear has move from the door.")
            print("You can go through it now.")
            bear_moved = True  #循环条件被修改
        elif choice == "taunt bear" and bear_moved: 
            dead("The bear gets pissed off and chews your leg off.")
        elif choice == "open door" and bear_moved:
            gold_room()
        else:
            print("I got no idea what that means.")


def cthulhu_room():
    print("Here you see the great evil Cthulhu.")
    print("He, it, whatever stares at you and you go insane.")
    print("Do you flee for your life or eat you head?")

    choice= input("> ")

    if "flee" in choice:
        start()
    elif "head" in choice:
        dead("Well that was tasty!")
    else:
        cthulhu_room()


def dead(why):
    print(why, "Good job!")
    exit()

def start():
    print("You are in a dark room.")
    print("There is a door to your right and left.")
    print("Which one do you take?")

    choice= input("> ")

    if choice == "left":
        bear_room()
    elif choice == "right":
        cthulhu_room()
    else:
        print("You stumble arount the room until you starve.")


start()

36.调试和设计

小结：这节主要讲了判断语句if及循环语句while,for的循环规则，复杂的程序一部分一部分运行起来，不要写了一大串再去运行

if语句规则	1.每条if都需要包含一个else 2.if语句嵌套不要超过两层 3.布尔测试应该相对简单一些，如果很复杂，要先将运算事先放到一个变量中
循环语句规则	1.在永不停止时使用while语句 2.尽量使用for语句

37.复习各种符号（略）

38.列表的操作

小结：数据结构是组织数据的正式方式，其中最常用的数据结构即为列表，就像一摞纸牌，两者对比：

列表	纸牌
有序的列表	纸牌从头到尾有序排列
要储存的东西	即纸牌本身内容
随机访问	可以从纸牌中任意抽取一张
线性	如果要找到某张牌，可以从第一张开始寻找
通过索引	得知位置后可以找出

练习：

ten_things = "Apples Oranges Crows Telephone Light Sugar"
stuff = ten_things.split(" ") # 根据空格进行slipt
# print(">>>",ten_things)
print(f"Wait! there are just {len(stuff)} things in that list. Let's fix that.")
# print(">>>",stuff)

more_stuff = ["Day", "Night", "Song", "Frisbee", "Corn", "Banana", "Girl", "Boy"]
# print(">>>",more_stuff)

# 将more_stuff列表中从前往后数删除的第一个赋值为next_oneone
while len(stuff) != 10:
    next_one = more_stuff.pop(0)  #.pop()默认是从后往前
    print("Adding: ", next_one)
    # print(">>>Now more_stuff list exists: ", more_stuff)
    stuff.append(next_one)
    print(f"There are {len(stuff)} items now,\n they are {stuff}")

print("Let's do some things with stuff.")

print(stuff[1])
print(stuff[-1])
print(stuff.pop())
# print(">>>",stuff)
print(' '.join(stuff))  #在stuff的元素之间插入空格
print('#'.join(stuff[3:5]))  #在基数为3和4的元素之间插入 # ，同range一样，上限不在内原则

课后练习需要用for语句来替换一下这里的while，11-16替换结果如下：

for i in more_stuff:
    stuff.append(i)
    if len(stuff) == 10:
        break
    print(f"There are {len(stuff)} items now,\n they are {stuff}")
    print(stuff)