Python练习一

1、使用while循环输入 1 2 3 4 5 6    8 9 10

i=1
while i<=10:
    if i==7:
        i +=1
        continue
    print(i)
    i +=1

2、求1-100的所有数的和

j = 1
sum = 0
while j <= 100:
    sum +=j
    j += 1
print("1-100的所有数的和:")
print(sum)

3、输出 1-100 内的所有奇数

k = 1
count = 0
print("输出 1-100 内的所有奇数")
while k <=100:
    if k % 2 ==0:
        k += 1
        continue
    else:
        count += 1
        print(k)
        k += 1
print("总共个数：")
print(count)

4、输出 1-100 内的所有偶数

a = 1
count = 0
print("输出 1-100 内的所有偶数")
while a <=100:
    if a % 2 !=0:
        a += 1
        continue
    else:
        count += 1
        print(a)
        a += 1
print("总共个数：")
print(count)

5、求1-2+3-4+5 ... 99的所有数的和

m = 1
n = 2
sum = 0
while m <= 99:
    print(m,n)
    sum += m
   # print(sum)
    if n > 99:
        print(n)
        break
    else:
        sum -=  n
    m += 2
    n += 2
print("1-2+3-4+5 ... 99的所有数的和:")
print(sum)

6、用户登陆（三次机会重试)

count2 = 1
name = raw_input("请输入用户名：")#用户名没有判断
while count2 < 4:
    password = raw_input("请输入密码：")
    if password == "123" : #密码有3次机会
        print("恭喜你，登录成功~")
    else:
        print("抱歉，密码输入错误~")
        count2 += 1
        continue

count1 = 1
count2 = 1
while count1 < 4: #用户名有三次机会
    name = raw_input("请输入用户名：")
    if name == "jessie":
        count1 += 1
        while count2 < 4:
            password = raw_input("请输入密码：")
            if password == "123" :#密码有三次机会
                print("恭喜你，登录成功~")
            else:
                print("抱歉，密码输入错误~")
                count2 += 1
    else :
        print("很抱歉，用户名不存在~")
        count1 += 1