Python语言和标准库（第一章：做出决策）

>>>"Pumpkin"=="pumpkin"
False
>>>"Pumpkin".lower()=="pumpkin".lower()
True
>>>"pumpkin".upper()
‘PUMPKIN‘

>>>not True
False
>>>not 5
False
>>>not 0
True
>>>Not True
报错

>>>True and True
True
>>>False and True
False

>>>True or False
True

>>>if 1>2:
           print("No it is not!")
>>>if 2>1:
           print("Yes it is!")

yes it is!

>>>omelet_ingredients = {"egg":2,"mushroom":5,"pepper":1,"cheese":1,"milk":1}
>>>fridge_contents+
{"egg":10,"mushroom":20,"pepper":3,"cheese":2,"tomato":4,"milk":15}
>>>have_ingredients = [False]
>>>if fridge_contents["egg"]>omelet_ingredients["egg"]:
            have_ingredients[0] = True
        have_ingredients.append("egg")

>>>print(have_ingredients)
[True,‘egg‘]

>>>OJ_price = 2.50
>>>if OJ_price<1.25:
           print("Get one, Im thirsty.")
       elif OJ_price<=2.00:
           print("Ummm........sure,but Ill drink it slowly.")
       else:
           print("I dont have enough money . Never mind.")


I dont have enough money.Never mind.

>>>i = 10
>>>while i>0:
print("Lift off in:")
print(i)
i= i -1

>>>for i in range(10,0,-1):
print("T_minus:")
print(i)
...

T-minus:
10
T-minus:
9
T-minus:
8
.
.
.

>>>age = 0
>>>while True:
how_old = input("Enter your age:")
if how_old =="No":
    print("dont be ashamed of your age!")
    break
num = int(how_old)
age = age+num
print("Your age is:")
print("that is old!")
...
Enter your age:1
Your age is:
1
that is old!
Enter your age:2
your age is:3
...
Enter your age:no
dont be ashamed of your age!

>>>for food in ("pate","cheese","rotten apple","crackers","whip cream","tomato soup"):
...         if food[0:6] == "rotten":
...             continue
...             print("hey you can eat %$"% food)

>>>fridge_contents = {"egg:8","mushroom":20,"pepper":3,"cheese":2,"tomato":4,"milk":13}
>>>if fridge_contents["orange juice"]>3:
...        print("lets have some juice!")
...