For循环无法在同一文件描述符上运行两次 [英] For loop not working twice on the same file descriptor

问题描述

该代码未进入第二个for循环.我没有在任何地方修改文件描述符.为什么会这样呢?

The code is not entering the second for loop. I am not modifying the file descriptor anywhere. Why is that happening?

import os
import re

path = '/home/ajay/Desktop/practice/ajay.txt'
os.system('ifconfig>>path')
fd = open(path,'r+')
interfaces = []
tx_packets = []

for line in fd:

    if(re.search(r'(\w+)\s+\Link',line)):
    inter = re.match(r'(\w+)\s+\Link',line)
    interface = inter.group(1)
    interfaces.append(interface)

for lines in fd:

    if(re.search(r'\s+TX packets:(\d+)',lines)):
        tx_packs = re.match(r'\s+TX packets:(\d+)',lines)
        tx_pack = tx_packs.group(1)
        tx_packets.append(tx_pack)


print interfaces
print  tx_packets

推荐答案

因为for lines in fd:会将读取指针，文件指针或任何被调用的内容放在文件末尾.在您的for循环之间调用fd.seek(0)

Because for lines in fd: will place the read pointer, file pointer or whatever it's called at the end of the file. Call fd.seek(0) in between your for loops

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