how to read the lines from line 7 to line 265 in python?

Question

I am reading a .txt file but I want to read the file from line number 6 till line number 265. can some tell me how to do that ? Output.txt :

my code:

    h = httplib.HTTPSConnection(host, port)

h.set_debuglevel(1)

headers = {

    "Content-Type": "multipart/form-data; boundary=%s" % (boundary,),

    "Connection": "Keep-Alive",

}

h.request('POST', uri, body, headers)

res = h.getresponse()
filehandle = open("Output.txt", "wb")
filehandle.write(res.read())
import itertools
with open("Output.txt", "rb") as infile, open("output1.txt", "wb") as outfile:
    for line in itertools.islice(infile, 6, 265):
        outfile.write(line)
filehandle.close()

the above code is just reading line 6 but how to read from line 6 to line 265 ?

Answer 1

I recommend using islice from the itertools package.

import itertools

 with open("input.txt", "rb") as infile, open("output.txt", "wb") as outfile:
     for line in itertools.islice(infile, 6, 265):
         outfile.write(line)

In response to your comment requesting to read the first 6 and last 12 into a file, and the rest into another file, I would do something like the following

from collections import deque
from itertools import islice 

with open("input.txt", "rb") as infile, open("output1.txt", "wb") as outfile1, open("output2.txt", "rb") as outfile2:
    outfile.write(''.join(islice(infile, 6)))

    q = deque(islice(infile, 12))
    outfile2.write(''.join(q))

    for line in infile:
        q.append(line)
        outfile2.write(q.popleft())

    outfile.write(''.join(q))

The idea here is to

1. Write the first 6 lines to the first file
2. Write the next 12 lines to the second file and populate a queue with them
3. Push new lines onto the queue and pop old lines off until the input file is exhausted
4. Write the 12 lines remaining in the queue (the last 12 lines) to the first output file.

Answer 2

Here is an example. It prints line number 6 till line number 265.

with open("file", "rb") as fp:
    for linenr, line in enumerate(fp):
        if linenr > 264:
            break
        elif linenr >= 5:
            print(line)

Please note that linenr == 5 for the 6th line and 264 for the 265th line.

---

You can use following example to save the selected lines to another file.

with open("fileoutput", "wb") as outputfile, open("fileinput", "rb") as inputfile:
    for linenr, line in enumerate(inputfile):
        if linenr > 264:
            break
        elif linenr >= 5:
            outputfile.write(line)

Answer 3

as you mentions in one of yours comments that you want to read the first 4 lines and the finals 12 lines of the file, you can use the answer of @DavisYoshida to the first part and this to the final part

from collections import deque

def tail(iterable,n=None):
    """Return an iterator over the last n items, if n is none return a iterator over all elemens
       in iterable save the first

       tail('ABCDEFG',3) --> E F G
       tail('ABCDEFG')   --> B C D E F G """
    if n is None:
        resul = iter(iterable)
        next(resul,None)
        return resul
    return iter(deque(iterable, maxlen=n))

this a recipe from the documentation of itertools with a little changes

for example

>>> with open("Output.txt","rb") as infile:
        for i,line in enumerate(islice(infile,0,4),1):
            print(i,"-->",line)
        print()
        for i,line in enumerate(tail(infile,12)):
            print(-(12-i),"-->",line)

1 --> b'----Nuance_NMSP_vutc5w1XobDdefsYG3wq\n'
2 --> b'Content-Disposition: form-data; name="Audio"; paramName="TEXT_TO_READ"\n'
3 --> b'Content-Type: audio/x-wav;codec=pcm;bit=16;rate=8000\n'
4 --> b'Nuance-Context: f886d51f-84f7-491e-9412-1d1f4e33304e\n'

-12 --> b'Content-Disposition: form-data; name="Audio"; paramName="TEXT_TO_READ"\n'
-11 --> b'Content-Type: audio/x-wav;codec=pcm;bit=16;rate=8000\n'
-10 --> b'Nuance-Context: f886d51f-84f7-491e-9412-1d1f4e33304e\n'
-9 --> b'\n'
-8 --> b'\n'
-7 --> b'----Nuance_NMSP_vutc5w1XobDdefsYG3wq\n'
-6 --> b'Content-Disposition: form-data; name="QueryResult"\n'
-5 --> b'Content-Type: application/JSON; charset=utf-8\n'
-4 --> b'Nuance-Context: f886d51f-84f7-491e-9412-1d1f4e33304e\n'
-3 --> b'\n'
-2 --> b'{"TTSStatus":"Success","result_type":"NVC_TTS_CMD","NMAS_PRFX_SESSION_ID":"28fdbb23-a278-4e7d-8275-a046071823b3","NMAS_PRFX_TRANSACTION_ID":"1"}\n'
-1 --> b'----Nuance_NMSP_vutc5w1XobDdefsYG3wq--'
>>>