CS50P: 1. Conditionals

运算符

python中有 >= 和 <= ，其余和C一样

python支持 90 <= score <= 100

C	Python
||	or
&	and

布尔运算

True or False

选择语句

if

if x < y:print("x is less than y")
if x > y:print("x is greater than y")
if x == y:print("x is equal to y")

• :
• .... 四个缩进，表示只有当 if 为真，该语句才能被执行。有缩进是一个代码块

代码的逻辑：三个 if 都会被执行

elif

if x < y:print("x is less than y")
elif x > y:print("x is greater than y")
elif x == y:print("x is equal to y")

else

if x < y:print("x is less than y")
elif x > y:print("x is greater than y")
else:print("x is equal to y")

match

类似 switch

原：

if name == "Harry" or name == "Hermione" or name == "Ron":		#字符串 ==print("Gryffindor")
elif name == "Draco":print("Slytherin")
else:print("Who?")

match：

match name:case "Harry" | "Hermione" | "Ron": print("Gryffindor")case "Draco":print("Slytherin")case _:print("Who?")

• case _: 表示else
• | 在case中表示或

Pythonic Expressions

def is_even(x):return True if x % 2 == 0 else False

def is_even(x):return x % 2 == 0