Python中的示例与其他示例并无太大不同。模拟PHP脚本：
class StrategyExample:
def __init__(self, func=None):
if func:
self.execute = func
def execute(self):
print("Original execution")
def executeReplacement1():
print("Strategy 1")
def executeReplacement2():
print("Strategy 2")
if __name__ == "__main__":
strat0 = StrategyExample()
strat1 = StrategyExample(executeReplacement1)
strat2 = StrategyExample(executeReplacement2)
strat0.execute()
strat1.execute()
strat2.execute()
输出：
Original execution
Strategy 1
Strategy 2
主要区别在于：
我给你看的方式 但是该方法将是静态的，不会传递“ self”参数。
使用类名：
StrategyExample.execute = func
在这里，所有实例都将func作为execute方法，并self作为参数传递。
strat0.execute = types.MethodType(executeReplacement1, strat0)
或使用Python 2，还需要更改实例的类：
strat0.execute = types.MethodType(executeReplacement1, strat0, StrategyExample)
与第一个示例一样，这会将新方法绑定到strat0和only strat0。但是start0.execute()会self以争论的形式通过。
如果需要在函数中使用对当前实例的引用，则可以合并第一个和最后一个方法。如果你不：
class StrategyExample:
def __init__(self, func=None):
self.name = "Strategy Example 0"
if func:
self.execute = func
def execute(self):
print(self.name)
def executeReplacement1():
print(self.name + " from execute 1")
def executeReplacement2():
print(self.name + " from execute 2")
if __name__ == "__main__":
strat0 = StrategyExample()
strat1 = StrategyExample(executeReplacement1)
strat1.name = "Strategy Example 1"
strat2 = StrategyExample(executeReplacement2)
strat2.name = "Strategy Example 2"
strat0.execute()
strat1.execute()
strat2.execute()
你会得到：
Traceback (most recent call last):
File "test.py", line 28, in <module>
strat1.execute()
File "test.py", line 13, in executeReplacement1
print self.name + " from execute 1"
NameError: global name 'self' is not defined
因此正确的代码将是：
import sys
import types
if sys.version_info[0] > 2: # Python 3+
create_bound_method = types.MethodType
else:
def create_bound_method(func, obj):
return types.MethodType(func, obj, obj.__class__)
class StrategyExample:
def __init__(self, func=None):
self.name = "Strategy Example 0"
if func:
self.execute = create_bound_method(func, self)
def execute(self):
print(self.name)
def executeReplacement1(self):
print(self.name + " from execute 1")
def executeReplacement2(self):
print(self.name + " from execute 2")
if __name__ == "__main__":
strat0 = StrategyExample()
strat1 = StrategyExample(executeReplacement1)
strat1.name = "Strategy Example 1"
strat2 = StrategyExample(executeReplacement2)
strat2.name = "Strategy Example 2"
strat0.execute()
strat1.execute()
strat2.execute()
这将输出预期的结果：
Strategy Example 0
Strategy Example 1 from execute 1
Strategy Example 2 from execute 2
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