Python read text file from second line to fifteenth [closed]

Question

I have a text file and I need to read from the seconds line to to 15th line including. I've tried some methods but no method worked for me... I'd be happy if anyone could help me ... thanks a lot!

Mickel

Answer 1

Use itertools.islice:

from itertools import islice
with open('filename') as fin:
    for line in islice(fin, 1, 16):
        print line

Burchell

+1 best way to do this. – Tenancy

@AshwiniChaudhary Why is it the best way? Because islice uses generator expressions? – Desinence

@Desinence islice is a fast and pythonic way to get a slice from an iterator, It does loops over the iterator but that happens internally at C speed. – Tenancy

+1 This seems very elegant. I wasn't aware of islice before. itertools is quite the treasure chest! – Phage

Answer 2

If the file isn't very big:

with open('/path/to/file') as f:
    print f.readlines()[1:15]

Campo

If the file is huge this will load everything into memory. – Tenancy

Answer 3

I think you can just read the lines and take the ones you need

For example:

with open("a.txt", "r") as text_file:
    data = text_file.readlines()

now data[1] will be second line and data[14] will be 15th, so you can slice it as such data[1:14]

Then you can put them into a variable and that's it

Instil

Open files in a with block. – Brocky

Answer 4

Jon's answer is definitely a more pythonic and clean approach.

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Alternatively, you can use enumerate():

with open("file", 'r') as f:
    print [x for i, x in enumerate(f) if 1 <= i <= 15]

Note, that this will loop over all lines in a file. It's better to break the loop after the 15th line, like this:

with open("file", 'r') as f:
    for i, x in enumerate(f):
        if 1 <= i <= 15:
            print x
        elif i > 15:
            break

Raja