python将对象名的字符串类型，转化为相应对象的操作方法-白红宇

python将对象名的字符串类型，转化为相应对象的操作方法

阅读量：4451 次

发布时间：2019-06-07

本文共 5312 字，大约阅读时间需要 17 分钟。

在实际使用Python的过程中，遇到了一个问题，就是定义一个数组，数组内容为对应类名字的字符串。

此时在调用对应的类，生成实例时，需要将字符串转化为相应的类，之后再进行实例化。

# coding : utf-8 import time from OffLineGateway import OffLineGateway from OffLineTS import OffLineTS import copy class PlayTest(object):     def __init__(self, file):         self.file = file         get_obj = file.split('.')[0]         module = __import__(get_obj)         self.server_name = getattr(module, get_obj)()         self.test_param_file = r'./' + file.split('.')[0] + r"param" + time.strftime("%H%M%S", time.localtime()) + ".txt"         self.test_func_file = r'./' + file.split('.')[0] + r"func" + time.strftime("%H%M%S", time.localtime()) + ".txt"     def set_function(self, num, variable):         flag = 0         content = ""         file_object = open(self.file, 'r', encoding='utf-8')         for line in file_object:             string = r'    def test_exe_param' + str(num) + r'(self):'             if line.__contains__(string) and flag == 0:                 flag = 1                 content += '    def test_exe_param' + str(num) + '_' + str(variable) + r'(self):\n'             else:                 if line.__contains__("    def test_exe_param") and flag == 1:                     break                 elif flag == 1:                     if line.__contains__('self.assertFalse(True, '):                         content += line                         content += '\n        if get_return_code != "000000":\n'                         content += '            self.assertEqual(get_errormsg, self.server.read_config' \                                    '(self.config_file, get_return_code))\n'                         content += '        else:\n'                         content += '            self.assertFalse(True, "没有对应的错误码。")\n\n'                         break                     else:                         if line.__contains__('result = self.server.get_result(self.ip, self.param'):                             new_line = line.replace(str(num), str(num) + "_" + str(variable))                             content += '\n' + new_line                         elif line.__contains__('self.param' + str(num) + '['):                             new_line = line.replace(str(num), str(num) + "_" + str(variable))                             content += '\n' + new_line                         else:                             content += line                 else:                     pass         return content     def get_param(self):         of = self.server_name.setUp()         for i in range(1, 100):             try:                 j = 1                 param = eval("of['self'].param" + str(i))                 print(i)                 port = list(param.keys())[0]                 temp = copy.deepcopy(param)                 for key in param[port][1].keys():                     param[port][1][key] = ""                     with open(self.test_param_file, "a", encoding="utf-8") as f:                         f.write("        self.param" + str(i) + "_" + str(j) + " = " + str(param) + "\n")                     # print("self.param" + str(i) + "_" + str(j) + " = " + str(param))                     with open(self.test_func_file, "a", encoding="utf-8") as f:                         f.write(self.set_function(i, j))                     # print(self.set_function(i, j))                     j += 1                     param[port][1][key] = temp['gw'][1][key]                 for key in param[port][1].keys():                     param[port][1][key] = ""                 with open(self.test_param_file, "a", encoding="utf-8") as f:                     f.write("        self.param" + str(i) + "_" + str(j) + " = " + str(param) + "\n")                 # print("self.param" + str(i) + "_" + str(j) + " = " + str(param))                 with open(self.test_func_file, "a", encoding="utf-8") as f:                     f.write(self.set_function(i, j))                 # print(self.set_function(i, j))                 j += 1                 param[port][1] = {}                 with open(self.test_param_file, "a", encoding="utf-8") as f:                     f.write("        self.param" + str(i) + "_" + str(j) + " = " + str(param) + "\n")                 # print("self.param" + str(i) + "_" + str(j) + " = " + str(param))                 with open(self.test_func_file, "a", encoding="utf-8") as f:                     f.write(self.set_function(i, j))                 # print(self.set_function(i, j))             except AttributeError as ae:                 print("没有了。")                 break if __name__ == '__main__':     file_name = ['OffLineGateway', 'OffLineTS']     for name in file_name:         print(name)         test = PlayTest(name + ".py")         test.get_param()         time.sleep(1.0)

+++++++++++++++++++++++++++++++++++++++分割线+++++++++++++++++++++++++++++++++++++++

方法一：

class obj(object):

pass

a = eval('obj()')

方法二：

如果是经常需要这样可以

#将用来创建对象的字符串预编译成code对象.

create_obj = compile('obj()', 'create_obj.py', 'eval')

#需要创建的时候, 直接用code对象, 这样会有效率上的提升. #因为code对象是预编译过的, 而不用每次去编译

a = eval(create_obj)

方法三：