Python3通過函式名呼叫函式的幾種場景實現
阿新 • • 發佈:2020-07-14
一、說明
之前寫了一篇“Python執行系統命令教程”講了如何執行系統命令。
除了執行系統命令外,我們有時還需要動態地執行一些python程式碼,有經驗的朋友就會知道可以使用內建函式eval實現這一需求,如eval("print(__file__)"),這還是比較簡單的。
但如果要動態執行一個函式,講的資料就會少一點,這次就要看這個需求該如何實現。
二、通過eval實現
2.1通過eval呼叫同一個類內的函式
class TestA: def __init__(self): self.config_dict = {View Code"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"] # 就直接呼叫。如果有其他引數,一樣地傳就好了 # 另外也可以是"be_called_function_name"是"be_called_function",然後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通過eval呼叫同一個檔案內的一級函式
class TestA: def __init__(self): self.config_dictView Code= { "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"] # 就直接呼叫。如果有其他引數,一樣地傳就好了 # 另外也可以是"be_called_function_name"是"be_called_function",然後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、通過getattr實現
3.1 通過函式名呼叫同一個類內的函式
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傳self即可 be_called_function = getattr(self, self.config_dict["be_called_function_name"]) # 就直接呼叫。如果有其他引數,一樣地傳就好了 be_called_function() pass def be_called_function(self): print("here is be_called_function.") if __name__ == "__main__": obj = TestA() obj.active_call_function()View Code
3.2 通過函式名呼叫其他類的函式
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傳被呼叫的函式所在的類的類例項 testb_obj = TestB() be_called_function = getattr(testb_obj, self.config_dict["be_called_function_name"]) # 就直接呼叫。如果有其他引數,一樣地傳就好了 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()View Code
3.3 通過函式名呼叫同文件的一級函式
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傳當前模組名 module_name = sys.modules['__main__'] be_called_function = getattr(module_name, self.config_dict["be_called_function_name"]) # 就直接呼叫。如果有其他引數,一樣地傳就好了 be_called_function() pass def be_called_function(): print("here is be_called_function.") if __name__ == "__main__": obj = TestA() obj.active_call_function()View Code
3.4 通過函式名呼叫在其他檔案的一級函式
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傳函式所在模組名 # __import__()傳函式所在檔案 module_name = __import__("test_call_function_by_string1") be_called_function = getattr(module_name, self.config_dict["be_called_function_name"]) # 就直接呼叫。如果有其他引數,一樣地傳就好了 be_called_function() pass if __name__ == "__main__": obj = TestA() obj.active_call_function()View Code