python检测当前网卡流量信息，用于查看实时网速

可以用来检测是否有挖矿程序在运行的一个子条件

 # coding:utf-8
 __author__ = 'chenhuachao'
 import wmi
 import time
 import platform

 def get_network_flow(os):
     '''监控window平台下网卡的实时的流量信息
     通过当前总流量和一秒后的总流量的差值，来统计实时的网卡流量信息;
     返回的流量单位是KB
     '''
     if os == "Windows":
         c = wmi.WMI()
         for interfacePerTcp in c.Win32_PerfRawData_Tcpip_TCPv4():
             sentflow = float(interfacePerTcp.SegmentsSentPersec)  #已发送的流量
             receivedflow = float(interfacePerTcp.SegmentsReceivedPersec) #接收的流量
             present_flow = sentflow+receivedflow    #算出当前的总流量
         time.sleep(1)
         for interfacePerTcp in c.Win32_PerfRawData_Tcpip_TCPv4():
            sentflow = float(interfacePerTcp.SegmentsSentPersec)  #已发送的流量
            receivedflow = float(interfacePerTcp.SegmentsReceivedPersec) #接收的流量
            per_last_present_flow = sentflow+receivedflow     #算出1秒后当前的总流量
         present_network_flow = (per_last_present_flow - present_flow)/1024
         print("当前流量为：{0}KB".format("%.2f"%present_network_flow))
         return "%.2f"%present_network_flow

 if __name__ =="__main__":
     os = platform.system()
     while 1:
         flow = get_network_flow(os)
         print("{0}KB".format(flow))