python将对象名的字符串类型，转化为相应对象的操作方法

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：

file_name  模块名  

 module = __import__(file_name)

 AClass = getattr(module, class_name_str)()

 a = AClass() 或

obj = new.instance(AClass)

方法四： 也可以使用global(），locals()，dir()这类获取对象名和对象对应的函数 

转自：http://www.th7.cn/Program/Python/201510/666094.shtml