1、条件判断

score = int(input("请输入学生成绩："))
if score>100 and score <0:
    print("请输入正确的成绩")
elif score<=100 and score >=90:
    print("优秀")
elif score < 90 and score >= 80:
    print("良好")
elif score <80 and score >= 60:
    print("及格")
else:
    print("不及格")

#若if代码块中无内容，可使用pass，pass代表空代码块，无实际意义

a = 10
if a%2 == 0:
    pass
else:
    print('该数为奇数')

2、while循环

count =0

while count<4:
    print(count)
    count = count+1

# break 循环中遇到break立即结束
# continue 循环里遇到continue就结束本次循环
print('----------------------------')

import random
number = random.randint(1,100)
print(number)
count = 0
while count <7:
    guess = int(input("请输入一个1至100的随机数："))
    count = count + 1
    if guess > number :
        print("猜大了")
    elif guess < number:
        print("猜小了")
    elif guess == number:
        print("猜对了")
        break
    # if count != 7:
    #     continue
    # else:
    #     print("错误次数用光了")
#可直接在while平级加else，while循环正常结束后会直接执行else中代码
else:
    print("错误次数用光了")

3、continue

number = 0
while number < 10:
    number = number + 1
    if number%2==0:
        continue
    print(number)

4、for循环、print、字符串输出
import datetime
for i in range(4):
    print("第",i+1,"次循环",sep="") #print 多个连接必须用sep作为间隔符
print("-----------------------")
#字符串格式化
username = 'linqian'
date = datetime.datetime.today()
print(type(date))
# msg = '欢迎'+username+'登录，'+'今天是'+date
msg2 = '欢迎%s登录，今天是%s' %(username,date)
# print(msg)
print("-----------------------")
print(msg2)