Python成长记十六（python中的

发布时间：2019-09-25 08:33:46编辑：auto阅读（1962）

    我们都知道python中没有switch case语句这种写法，那么我们怎样使用python实现同样的功能呢？

    其他语言的switch case语句语法如下：

     switch(n)
{
case 1:
  执行代码块 1
  break;
case 2:
  执行代码块 2
  break;
default:
  n 与 case 1 和 case 2 不同时执行的代码
}

    比如在JavaScript里可以这么写：

    var day=new Date().getDay();
switch (day)
{
case 0:
  x="Today it's Sunday";
  break;
case 1:
  x="Today it's Monday";
  break;
case 2:
  x="Today it's Tuesday";
  break;
case 3:
  x="Today it's Wednesday";
  break;
case 4:
  x="Today it's Thursday";
  break;
case 5:
  x="Today it's Friday";
  break;
case 6:
  x="Today it's Saturday";
  break;
default:
  x="Looking forward to the Weekend";
}

    那么在python中我们怎么样实现呢？

    解决方案：用字典映射代表switch case语句

    实现以上语句如下：

    import datetime

day = datetime.datetime.now().weekday()

def get_sunday():
    return "Today it's Sunday"
def get_monday():
    return "Today it's Monday"
def get_tuesday():
    return "Today it's Tuesday"
def get_wednesday():
    return "Today it's Wednesday"
def get_thursday():
    return "Today it's Thursday"
def get_friday():
    return "Today it's Friday"
def get_saturday():
    return "Today it's Saturday"
def get_default():
    return "Looking forward to the Weekend"

switcher = {
    0:get_sunday,
    1:get_monday,
    2:get_tuesday,
    3:get_wednesday,
    4:get_thursday,
    5:get_friday,
    6:get_default

}

dayName = switcher.get(day,get_default)()
print(dayName)

    总结：我们可以使用字典的方式实现switch语句

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