Python ping3批量测试IP地址的访问延迟

某域名背后的服务器都布置在国外，DNS服务器会将此域名解析到不固定的IP地址，其中某些IP地址在国内访问速度挺快，有些很慢，还有一些则根本没法访问。为提升访问的稳定性，我决定先找出访问速度最快的IP，而后修改hosts文件指向这个IP，省去DNS服务器的解析。
首先经过https://ping.chinaz.com/找出目标域名的所有IP地址，保存到txt文件中，每一个IP地址占一行(也能够使用逗号分割)。而后用python3的open读入文件，用ping3包的ping函数测试每一个IP地址的访问延迟，测试n次后求平均值。对于访问超时的IP地址，直接赋给它一个很长的时间，好比5000ms. 将IP地址及测试结果再写入另外一个文本文件。若从未使用过ping3，请先安装：pip install ping3
代码以下：

python

import ping3

fread=open(r"E:\PythonDevelop\IPList.txt",'r')
fwrite=open(r"E:\PythonDevelop\IPTest.txt",'w')
TargetIP=fread.readline()
n=3
while TargetIP:
    TotalTime=0.0
    for k in range(n):
        IPstrip=TargetIP.strip()
        PingTime=ping3.ping(IPstrip,timeout=1,unit='ms')
        if not PingTime:
            PingTime=5000.0
        TotalTime=TotalTime+PingTime
    print(IPstrip+','+str(int(TotalTime/n)))
    fwrite.writelines(IPstrip+','+str(int(TotalTime/3))+'\n')
    TargetIP=fread.readline()
fread.close()
fwrite.close()

ping函数的说明以下：
ping(dest_addr: str, timeout: int = 4, unit: str = 's', src_addr: str = None, ttl: int = 64, seq: int = 0, size: int = 56, interface: str = None) -> float
Send one ping to destination address with the given timeout.

服务器

   Args:
       dest_addr: The destination address, can be an IP address or a domain name. Ex. "192.168.1.1"/"example.com"
       timeout: Time to wait for a response, in seconds. Default is 4s, same as Windows CMD. (default 4)
       unit: The unit of returned value. "s" for seconds, "ms" for milliseconds. (default "s")
       src_addr: WINDOWS ONLY. The IP address to ping from. This is for multiple network interfaces. Ex. "192.168.1.20". (default None)
       interface: LINUX ONLY. The gateway network interface to ping from. Ex. "wlan0". (default None)
       ttl: The Time-To-Live of the outgoing packet. Default is 64, same as in Linux and macOS. (default 64)
       seq: ICMP packet sequence, usually increases from 0 in the same process. (default 0)
       size: The ICMP packet payload size in bytes. If the input of this is less than the bytes of a double format (usually 8), the size of ICMP packet payload is 8 bytes to hold a time. The max should be the router_MTU(Usually 1480) - IP_Header(20) - ICMP_Header(8). Default is 56, same as in macOS. (default 56)

less

Returns:
The delay in seconds/milliseconds or None on timeout.
dom

Raises:
PingError: Any PingError will raise again if `ping3.EXCEPTIONS` is True.
函数