其他語言中，switch語句大概是這樣的
switch (var)而python本身沒有switch語句，解決方法有以下3種:
a.使用dictionary
values =
values.get(var, do_default_stuff)()
b.使用lambda
result = [value](x)c.brian beck提供了乙個類 switch 來實現其他語言中switch的功能
# this class provides the functionality we want. you only need to look at
# this if you want to know how this works. it only needs to be defined
# once, no need to muck around with its internals.
class switch(object):
def __init__(self, value):
self.value = value
self.fall = false
def __iter__(self):
"""return the match method once, then stop"""
yield
self.match
raise stopiteration
def match(self, *args):
"""indicate whether or not to enter a case suite"""
ifself.fall or
not args:
return
true
elif
self.value in args: # changed for v1.5, see below
self.fall = true
return
true
else:
return
false
# the following example is pretty much the exact use-case of a dictionary,
# but is included for its simplicity. note that you can include statements
# in each suite.
v = 'ten'
for case in switch(v):
if case('one'):
1break
if case('two'):
2break
if case('ten'):
10break
if case('eleven'):
11break
if case(): # default, could also just omit condition or 'if true'
"something else!"
# no need to break here, it'll stop anyway
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