有关字典的这两个报警是怎么回事？

Question

代码如下

def cfg_device_relate(self):
        # 有效设备的参数
        self.eff_device_para = {}
        # 有效屏幕的参数
        self.eff_screen_para = {}
        # 有效项目（数值列表）
        self.eff_subject_para = []
        # 判断
        device_eff = self.cfg_para['识别设备'] in self.device_dict.keys()
        if (device_eff):
            self.eff_device_para = dict(self.device_dict[self.cfg_para['识别设备']])
            screen_eff = self.cfg_para['识别屏幕'] in self.eff_device_para.keys()
            # 判断项目
            if (screen_eff):
                self.eff_screen_para = self.eff_device_para[self.cfg_para['识别屏幕']]
                sub_eff = self.cfg_para['识别项目'] in self.eff_screen_para.keys()
                if (sub_eff):
                    self.eff_subject_para = list(self.eff_screen_para[self.cfg_para['识别项目']])

Pycharm

倒数第三行警告
Unresolved attribute reference 'keys' for class 'str'
倒数第一行警告
Expected type 'Union[SupportsIndex, slice]', got 'str' instead

Answer 1

1、第一个警告，"Unresolved attribute reference 'keys' for class 'str'"，它表示字符串类没有名为'keys'的属性或方法，self.eff_screen_para是一个字符串。
2、第二个警告，"Expected type 'Union[SupportsIndex, slice]', got 'str' instead"，表示期望的是一个索引值或切片对象，但实际传递的却是一个字符串。
self.cfg_para['识别项目']的结果是字符串。

self.eff_screen_para = self.eff_device_para[self.cfg_para['识别屏幕']]
sub_eff = self.cfg_para['识别项目'] in self.eff_screen_para.keys()
  if (sub_eff):
    self.eff_subject_para = list(self.eff_screen_para[self.cfg_para['识别项目']])

为了消除警告，可以使用isinstance函数来检查这两个字符串对象是否为字典类型，然后再调用keys方法。

修改后的代码如下：

def cfg_device_relate(self):
    # 有效设备的参数
    self.eff_device_para = {}
    # 有效屏幕的参数
    self.eff_screen_para = {}
    # 有效项目（数值列表）
    self.eff_subject_para = []
    # 判断
    device_eff = isinstance(self.cfg_para['识别设备'], dict)
    if device_eff:
        self.eff_device_para = dict(self.device_dict[self.cfg_para['识别设备']])
        screen_eff = isinstance(self.cfg_para['识别屏幕'], dict)
        # 判断项目
        if screen_eff:
            self.eff_screen_para = self.eff_device_para[self.cfg_para['识别屏幕']]
            sub_eff = isinstance(self.cfg_para['识别项目'], dict)
            if sub_eff:
                self.eff_subject_para = list(self.eff_screen_para[self.cfg_para['识别项目']])