how to read line by line from a textfile and pass the value using python

Question

I have a file "BatchLink.txt" which contains urls in new lines.I want to read these lines by lines and pass the argument linewise to a batch script.

Let's say, my batchlink.txt contains this data :-

http://link1
http://link2
http://link3
http://link4

Now, I want to read linewise and send this to a batch file one line at a time.This question is the continuation of my previous question Here. Right Now, I have this code :-

import requests
from bs4 import BeautifulSoup
import subprocess 

file = open("BatchLinks.txt", "w")
r = requests.get('http://www.crunchyroll.com/i-cant-understand-what-my-husband-is-saying')
soup = BeautifulSoup(r.text)
print soup.title
subtitles = soup.findAll('div',{'class':'wrapper container-shadow hover-classes'})
for episode in subtitles:
  x = episode.find_all('a')
  for a in x:
   #print a['href']

   z = a['href']

  l = 'http://www.crunchyroll.com'+ z
  print l
  file.write(l+'\n')

print '-----------------------------------------------------------------------------'

file.close()

file = open('BatchLinks.txt', "r")
lines = file.readlines()
print lines

if __name__ =="__main__":
    response = lines
    print(lines)
    p = subprocess.Popen("_start.bat", stdin = subprocess.PIPE)
    time.sleep(1)

    p.stdin.write(response) #Answer the question

    time.sleep(20)

But, right now, the problem is that it reads the lines simultaneosuly and send it to the batch file.Which returns me the output [] . I can't seem to get it work.Any help/guidance would be appreciated.

score 2 · Answer 1 · answered Oct 22 '15 at 10:36

2

file = open('BatchLinks.txt', "r")
lines = file.readlines()

Change that to a more up-to-date version:

with open('BatchLinks.txt', "r") as inf:
    for line in inf:
        do something with line

answered Oct 22 '15 at 10:36

Andrew J

33
6

score 0 · Answer 2 · answered Jul 08 '15 at 14:37

file = open('BatchLinks.txt', "r")
lines = file.readlines()

Change that to a more up-to-date version:

with open('BatchLinks.txt', "r") as inf:
    for line in inf:
        do something with line

This is very basic stuff. Use the manual! https://docs.python.org/2/library/stdtypes.html#file-objects

Anand S Kumar · Answer 3 · 2015-07-09T07:43:33.610

0

When you do - lines = file.readlines() - it reads all the lines from the file and returns it as a list , so lines is a list of all the lines in the file.

Then you are doing - p.stdin.write(response) - this sends the complete list over to the other process, you should iterate over the lines and send each line to a new process.

Example -

if __name__ =="__main__":
    for line in lines:
        print(line)
        p = subprocess.Popen("_start.bat", stdin = subprocess.PIPE)
        time.sleep(1)

        p.stdin.write(line.strip())

       time.sleep(20)

edited Jul 09 '15 at 07:43

answered Jul 08 '15 at 14:37

Anand S Kumar

88,551
18
188
176

tried.. same result.. it's send all at once and with the "\n". Don't want the newline character... – Xonshiz Jul 09 '15 at 07:26
if so, try this line - `p.stdin.write(line.strip())` – Anand S Kumar Jul 09 '15 at 07:43

score 0 · Answer 4 · answered Jul 08 '15 at 14:46

I see two issues: you need to write to the pipe line by line, and need to close the pipe after done.

Replace the following line:

p.stdin.write(response) #Answer the question

with this one:

for line in response:
    p.stdin.write(line)
p.stdin.close()

how to read line by line from a textfile and pass the value using python

4 Answers4