if

number = 23
guess = int(input('请输入数字:'))
if guess == number:
    print('你输入对了')
elif guess < number:
    print('你输入小了')
else:
    print('大了')

print("Done")

while

while number <= 3 :
    print(number)
    number = number + 1

函数

def sayHello():
    print("你好! Hello! おはようございます！")

sayHello() # 你好! Hello! おはようございます！

def sum(a,b):
    return a + b

print(sum(1,2)) # 3

def say(message,time="12"):
    print(message + " " + time)

say("message") #  message 12

def func(a,b=5,c=10):
    print('a is',a,'and b is',b,'and c is',c)

func(25) # a is 25 and b is 5 and c is 10