#使用while循环输入1 2 3 4 5 6   8 9 10
num = 1
while num <=11:
    if num == 7 or num == 11:
        num += 1
        continue
    print(num)
    num += 1

#输出 1-100 内的所有奇数
num = 1
while num <= 100:
    if  num % 2 == 1:
        print(num)
    num += 1

#输出 1-100 内的所有偶数
num = 1
while num <= 100:
    if num %2 == 0:
        print(num)
    num += 1

#求1-2+3-4+5 ... 99的所有数的和
a = ''
b = 0
for i in range(1,100):
    a += str(i)
    if i % 2 == 0:
        a += '+'
        b -= i
    else:
        a += '-'
        b += i
print('输出: \r\n %s \r\n计算结果:\r\n %s' % (a.rstrip('-'),b))

用户登陆(三次机会重试)
name="LJS"
pswd="123"
i=1
while i < 4:
    input_name = input("Username:")
    input_pswd = input("Password:")
    if input_name == name and input_pswd == pswd:
        print("Welcome to my program!")
        break
    else:
        print("The user name or password you entered is incorrect. Please enter again.")
        i += 1
        continue