Python3通过函数名调用函数的几种场景实现
一、说明
之前写了一篇“Python执行系统命令教程”讲了如何执行系统命令。
除了执行系统命令外,我们有时还需要动态地执行一些python代码,有经验的朋友就会知道可以使用内置函数eval实现这一需求,如eval("print(__file__)"),这还是比较简单的。
但如果要动态执行一个函数,讲的资料就会少一点,这次就要看这个需求该如何实现。
二、通过eval实现
2.1 通过eval调用同一个类内的函数
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class TestA: def __init__(self): self.config_dict = { "be_called_function_name": "self.be_called_function()", } pass def active_call_function(self): print("here is active_call_function.") be_called_function_name = self.config_dict["be_called_function_name"] # 就直接调用。如果有其他参数,一样地传就好了 # 另外也可以是"be_called_function_name"是"be_called_function",然后eval(be_called_function_name)() eval(be_called_function_name) pass def be_called_function(self): print("here is be_called_function.") if __name__ == "__main__": obj = TestA() obj.active_call_function()
2.2 通过eval调用同一个文件内的一级函数
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class TestA: def __init__(self): self.config_dict = { "be_called_function_name": "be_called_function()", } pass def active_call_function(self): print("here is active_call_function.") be_called_function_name = self.config_dict["be_called_function_name"] # 就直接调用。如果有其他参数,一样地传就好了 # 另外也可以是"be_called_function_name"是"be_called_function",然后eval(be_called_function_name)() eval(be_called_function_name) pass def be_called_function(): print("here is be_called_function.") if __name__ == "__main__": obj = TestA() obj.active_call_function()
三、通过getattr实现
3.1 通过函数名调用同一个类内的函数
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class TestA: def __init__(self): self.config_dict = { "be_called_function_name": "be_called_function", } pass def active_call_function(self): print("here is active_call_function.") # getaattr(module_name, function_name),module_name传self即可 be_called_function = getattr(self, self.config_dict["be_called_function_name"]) # 就直接调用。如果有其他参数,一样地传就好了 be_called_function() pass def be_called_function(self): print("here is be_called_function.") if __name__ == "__main__": obj = TestA() obj.active_call_function()
3.2 通过函数名调用其他类的函数
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class TestA: def __init__(self): self.config_dict = { "be_called_function_name": "be_called_function", } pass def active_call_function(self): print("here is active_call_function.") # getaattr(module_name, function_name),module_name传被调用的函数所在的类的类实例 testb_obj = TestB() be_called_function = getattr(testb_obj, self.config_dict["be_called_function_name"]) # 就直接调用。如果有其他参数,一样地传就好了 be_called_function() pass class TestB: def be_called_function(self): print("here is be_called_function.") if __name__ == "__main__": obj = TestA() obj.active_call_function()
3.3 通过函数名调用同文件的一级函数
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import sys class TestA: def __init__(self): self.config_dict = { "be_called_function_name": "be_called_function", } pass def active_call_function(self): print("here is active_call_function.") # getaattr(module_name, function_name),module_name传当前模块名 module_name = sys.modules['__main__'] be_called_function = getattr(module_name, self.config_dict["be_called_function_name"]) # 就直接调用。如果有其他参数,一样地传就好了 be_called_function() pass def be_called_function(): print("here is be_called_function.") if __name__ == "__main__": obj = TestA() obj.active_call_function()
3.4 通过函数名调用在其他文件的一级函数
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class TestA: def __init__(self): self.config_dict = { "be_called_function_name": "be_called_function", } pass def active_call_function(self): print("here is active_call_function.") # getaattr(module_name, function_name),module_name传函数所在模块名 # __import__()传函数所在文件 module_name = __import__("test_call_function_by_string1") be_called_function = getattr(module_name, self.config_dict["be_called_function_name"]) # 就直接调用。如果有其他参数,一样地传就好了 be_called_function() pass if __name__ == "__main__": obj = TestA() obj.active_call_function()