print("hello world!",end = " ")#不换行

 print("hello again")

 print("I like typing this.")

 print("This is fun.")

 print("Yay!Printing.")

 print("I'd much rather you 'not'.")

 print('I "said" do not touch this.')

 print("")

 # A comment, this is so you can read your program later.

 # Anything after the # is ignored by python.

 print("I could have code like this.")# and the comment after is ignored .

 # you can also use a comment to "disable" or comment out code:

 #print("This won't run.")

 print("This will run.")

 print("hi # there.")

 #  (#)的英文是octothorpe或者 pound character

 #数字和数学运算

 print("I will now count my chickens:")

 print("hens", 25 + 30 / 6)

 print("roosters", 100 - 25 * 3 % 4)

 print("Now I will count the eggs:")

 print(3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6)

 print("Is it true that 3 + 2 < 5 - 7?")

 print(3 + 2 < 5 - 7)

 print("what is 3 + 2 ?", 3 + 2)

 print("what is 5 - 7?", 5 -  7)

 print("Oh,that's why it's false.")

 print("How about some more.")

 print("Is it greater ?", 5 > -2)

 print("Is it greater or eequal ?", 5 >= -2)

 print("Is it less or equal ?", 5 <= -2)

 #变量和命名

 #汽车数量

 cars = 100

 #每辆汽车的运载人数

 space_in_a_car = 4

 #司机人数

 drivers = 30

 #乘客人数

 passengers = 90

 #空车数量

 cars_not_driven = cars - drivers

 #占用的汽车数量

 cars_driven = drivers

 #最大可运输的人数

 carpool_capacity = cars_driven * space_in_a_car  #capacity=容积，carpool=拼车

 #平均每台汽车上的人数

 average_passengers_per_car = passengers / cars_driven

 print("there are ",cars,"cars available.")

 print("There are only",drivers,"drivers availlable.")

 print("There will be ",cars_not_driven,"empty cars today.")

 print("We can transport ",carpool_capacity,"people today.")

 print("We have ",passengers,"to carpool today.")

 print("We need to put about",average_passengers_per_car,"in each car.")

 name = 'Zed A.Shaw'

 age = 35     #not a lie

 height = 74  #inches

 weight = 180 #lbs

 eyes = 'Blue'

 teeth = "White"

 hair = "Brown"

 print(f"Let's talk about {name}.")    #f代表格式化的意思format

 print(f"He's {height} inches tall.")

 print(f"He's {weight} pounds heavy.")

 print("Actually that's not too heavy.")

 print(f"He's got {eyes} eyes and {hair} hair.")

 print(f"His teeth are usually {teeth} depending on the coffee.")

 #this line is tricky, try to get it exactly right

 total = age + height + weight

 print(f"If I add {age}, {height}, and {weight}. I get {total}.") 

 tpyes_of_people = 10

 x = f"There are {tpyes_of_people} types of people."

 binary = "binary"

 do_not = "don't"

 y = f"Those who know {binary} and those who {do_not}."

 print(x)

 print(y)

 print(f"I said: {x} .")

 #还是格式化输出字符串，在输出的字符串外面带上''

 print(f"I also said: '{y}'.")

 hilarious = "False"

 joke_evaluation = "Isn't that joke so funny ?!{}"

 #输出Isn't that joke so funny ?!False

 #.format()括号里面的内容都是格式化输出

 print(joke_evaluation.format(hilarious))

 w = "This is the left side of ..."

 e = "a string with a right side."

 print(w + e)

 print("Mary had a little lamb.")

 print("Its fleece was white as {}.".format('snow'))

 print("and everywhere that Mary went.")

 print("." * 10)

 end1 = "c"

 end2 = 'h'

 end3 = 'e'

 end4 = 'e'

 end5 = 's'

 end6 = 'e'

 end7 = 'B'

 end8 = 'u'

 end9 = 'r'

 end10 = 'g'

 end11 = 'e'

 end12 = 'r'

 print(end1 + end2 + end3 + end4 + end5 + end6, end = " ")

 print(end7 + end8 + end9 +end10 + end11 + end12)

 formatter = "{} {} {} {}"

 print(formatter.format(1,2,3,4))

 print(formatter.format('one','two','three','four'))

 print(formatter.format(True,False,False,True))

 print(formatter.format(formatter,formatter,formatter,formatter))

 print(formatter.format(

       "Try your",

       "Own text here",

       "Maybe a poem",

       "Or a song about fear"))

 #这个习题使用了format函数，让它返回formatter变量到其他字符串中

 #当看到formatter.format（....）,相当于

 #1.取第一行定义的formatter字符串

 #2.调用它的format函数

 #3.给format传递四个参数，这些参数和formatter中的{}匹配

 #4.在formatter上调用format的结果是一个新字符串，其中的{}被四个变量所替换

 # Here's some new strange stuf(材料，原料),remember type it exactly.

 days = "mon tue wed thu fri sat sun"

 months = " jan\nfeb\nmar\napr\nmay\njun\njul\naug"

 print("here are the days:",days)

 print("Here are the months: ",months)

 print('''

 There's something going on here.

 with the three double-quotes.

 we'll be able to tpye as much as we like.

 even 4 lines if we want,or 5, or 6.''')

 #\\转义字符\

 #\t转义字符tab键缩进，水平制表符，一个制表符8个位置

 #\'输出'

 #\"输出“

 tabby_cat = "\tI'm tabbed in."

 persian_cat = "I'm split\non a line."

 backslash_cat = "I'm \\ a \\cat."

 fat_cat = """

 I'll do a list:

 \t* Cat food

 \t*Fishies

 \t*Catnip\n\t*Grass

 """

 print(tabby_cat)

 print(persian_cat)

 print(backslash_cat)

 print(fat_cat)