def extract_data(self):
        """从数据中获取到绘图相关的有用信息."""
        self.time_axis = []
        self.cpu_axis = []
        self.mem_axis = []
        self.timestamp_list = []
        plot_data = self.data.get("plot_data", [])
        # 按照时间分割线，划分成几段数据，取其中的最值
        for i in plot_data:
            timestamp = i["timestamp"]
            self.timestamp_list.append(timestamp)
            timestamp = round(timestamp, 1)
            cpu_percent = i["cpu_percent"]
            mem_gb_num = i["mem_gb_num"]
            date = datetime.fromtimestamp(timestamp)
            # 添加坐标轴
            self.time_axis.append(date)
            self.cpu_axis.append(cpu_percent)
            self.mem_axis.append(mem_gb_num)

        # 获取各种方法执行过程中的cpu和内存极值:
        self.get_each_method_maximun_cpu_mem()