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Python基础-1

2018-06-29 06:08:22来源：博客园阅读 ()

一、注释的写法

二、if else的用法

score = int(input(">>:"))
if score > 90:
    print("A")
elif score > 80:
    print("B")
elif score > 70:
    print("C")
elif score > 50:
    print("D")
else:
    print("不及格")

**缩进级别必须保持一致

三、运算符

2**10：表示2的十次方
5/2：结果为2.5
5//2：结果为2
+ 、-、 *、 /、 //取整、%

四、while循环 continue break

n=1
while n<=100:
    if n%2==0:
        print(n)
    n +=1
    if n==10:
        break

打印99乘法表：

1*1=1
1*2=2 2*2=4
1*3=3 2*3=6 3*3=9
1*4=4 2*4=8 3*4=12 4*4=16
1*5=5 2*5=10 3*5=15 4*5=20 5*5=25
1*6=6 2*6=12 3*6=18 4*6=24 5*6=30 6*6=36
1*7=7 2*7=14 3*7=21 4*7=28 5*7=35 6*7=42 7*7=49
1*8=8 2*8=16 3*8=24 4*8=32 5*8=40 6*8=48 7*8=56 8*8=64
1*9=9 2*9=18 3*9=27 4*9=36 5*9=45 6*9=54 7*9=63 8*9=72 9*9=81

n=1
while n<=9:
    m=1
    while m<=n:
        print(str(m)+"*"+str(n)+"="+str(m*n),end="\t")
        m+=1
    print()
    n+=1

五、字符格式化输出

占位符：%s s = string
%d d = digit 整数
%f f = float 浮点数，约等于小数,保留小数点后六位

name = input("name:")
age = int(input("age:"))
salary = input("salary:")
if salary.isdigit():
    salary = int(salary)
else:
    # print("must input digit")
    exit("must input digit")
mesg = '''
-------info of %s ------
name: %s
age: %s  #%d
salary: %s
you will be retired in %s years
------------------------
''' %(name,name,age,salary,65-age)
print(mesg)

for i in range(1,5,2): #2表示步长
print(i) 结果为1，3

username="gdj"
password="123456"
for i in range(3):
    if input("username:")==username and input("password:")==password:
        print("welcome %s" %username)
        break
    else:
        print("invalide username or password")
else:
    print("太笨了")

六、列表

列表创建方式：a=list() 或者a=[]
统计出现的次数：a=["a","to","tt","to","to"].count("to")
排序： a.sort(reverse=true) 从大到小

七、购物车

product_list=[
    ('mars',9000),
    ('hadoop',120),
    ('tsl',120000),
    ('book',99),
    ('bike',600)
]
saving=input("please input your money:")
shopping=[]
if saving.isdigit():
    saving=int(saving)
    while True:
        for i,v in enumerate(product_list,1):
            print(i,'<<<<<<',v)
        choice=input('输入购买商品的编号[退出:q]')
        if choice.isdigit():
            choice=int(choice)
            if choice>0 and choice <=len(product_list):
                if product_list[choice - 1][1] <= saving:
                    shopping.append(product_list[choice - 1])
                    saving -= product_list[choice - 1][1]
                else:
                    print('您的余额不足，还剩%s元'%saving)
                print(shopping)
            else:
                print('编码不存在')
        elif choice=='q':
            print('您已购买如下商品=============')
            rest=[]
            for i in range(0,len(shopping)):
                id = 1
                for j in range(i+1,len(shopping)):
                    if shopping[i]==shopping[j]:
                        id +=1
                if not shopping[i] in rest:
                    print(shopping[i],id)
                    rest.append(shopping[i])
            print('您还剩%s元'%saving)
            break
        else:
            print('输入的编码不对')
else:
    print('输入的钱格式不对')