纯Python中的Switch-Case
项目描述
switchcase 在纯Python中实现了简单的Switch-Case结构。
在内部，switch 函数通过简单地返回一个包含匹配函数的长度为1的列表来工作。整个实现只有3行长
from operator import eq
def switch(value, comp=eq):
return [lambda match: comp(match, value)]基本用法
>>> from switchcase import switch
>>> def func(x):
... for case in switch(x):
... if case(0):
... print("x was 0")
... break
... if case(1):
... print("x was 1")
... break
... else:
... print("x was unmatched")
>>> func(0)
"x was 0"
>>> func(1)
"x was 1"
>>> func(2)
"x was unmatched"自定义比较
默认情况下，switch 使用 operator.eq 来比较传递给 switch 的值和随后传递给 case 的值。您可以通过将比较器函数作为第二个参数传递给 switch 来覆盖此行为。
>>> import re
>>> from switchcase import switch
>>> def f(x):
... out = []
... for case in switch(x, comp=re.match):
... if case("foo_bar"):
... out.append(0)
... break
... if case("foo_.*"):
... out.append(1)
... if case(".*_bar"):
... out.append(2)
... return out
>>> f("foo_bar")
[0]
>>> f("foo_notbar")
[1]
>>> f("notfoo_bar")
[2]
>>> f("foo____bar")
[1, 2]