Reading from text

[oamram]

Hi All,
new to python. i have a directory with about 50 text file and i need to
iterate through them and get
line 7 to 11 from each file and write those lines into another file(one file
that will contain all lines).

Cheers, Omer.

 

[JB]

oamram a écrit :

Hi All,
new to python. i have a directory with about 50 text file and i need to
iterate through them and get
line 7 to 11 from each file and write those lines into another file(one file
that will contain all lines).

First create a function that read and parse one file

Then create a loop that call this function for each file in a directory

Modules to read :

http://www.python.org/doc/2.5.2/tut/node9.html#SECTION009210000000000000000
http://docs.python.org/library/os.html


Julien

 

[bearophileHUGS]

oamram:

i have a directory with about 50 text file and i need to
iterate through them and get
line 7 to 11 from each file and write those lines into another
file(one file that will contain all lines).

Files can be iterated line-by-line, so this idiom:

for line in file: ...

will give you the lines, with newline. Once you have debugged that,
you can use the standard module glob (http://docs.python.org/library/
glob.html#module-glob ) to iterate on files.

If you have more problems, show use the code you have written and we
may suggest improvements.

Bye,
bearophile

 

[MRAB]

oamram:

Files can be iterated line-by-line, so this idiom:

for line in file: ...

will give you the lines, with newline. Once you have debugged that,
you can use the standard module glob (http://docs.python.org/library/
glob.html#module-glob ) to iterate on files.

[snip]
Or:

for index, line in enumerate(my_file): ...

where index will give you the line number (starting from 0, so you'll
want lines 6 to 10). You can break out of the loop when you have all the
lines you want.

 

[Tim Chase]

Assuming this is a real task and not a homework problem, then

I'd do it this way:

$ cd [directory containing 50 test files]
$ (for file in *; do head -n11 $file | tail -n5; done) >/path/to/results-file.txt

I'd use sed:

sed -ns 7,11p /source/path/*.txt >/path/to/results.txt

hard to get much more concise than that with any common tool

-tkc

 

[Aahz]

Assuming this is a real task and not a homework problem, then
I'd do it this way:

$ cd [directory containing 50 test files]
$ (for file in *; do head -n11 $file | tail -n5; done) >/path/to/results-file.txt

I'd use sed:

sed -ns 7,11p /source/path/*.txt >/path/to/results.txt

hard to get much more concise than that with any common tool

But you do have to learn sed. Avoiding that is precisely why I stick
with Python.

 

[Paul McGuire]

Hi All,
new to python. i have a directory with about 50 text file and i need to
iterate through them and get
line 7 to 11 from each file and write those lines into another file(one file
that will contain all lines).

import glob
file("output.txt","w").write('\n'.join( "".join(f.readlines()
[7:11+1]) ) for f in glob.glob("targetdir/*.txt"))

-- Paul

 

[Steve Holden]

Assuming this is a real task and not a homework problem, then
I'd do it this way:

$ cd [directory containing 50 test files]
$ (for file in *; do head -n11 $file | tail -n5; done) >/path/to/results-file.txt

I'd use sed:

sed -ns 7,11p /source/path/*.txt >/path/to/results.txt

hard to get much more concise than that with any common tool

But you do have to learn sed. Avoiding that is precisely why I stick
with Python.

+1 [cross-platform] QOTW

 

[Steve Holden]

Assuming this is a real task and not a homework problem, then
I'd do it this way:

$ cd [directory containing 50 test files]
$ (for file in *; do head -n11 $file | tail -n5; done) >/path/to/results-file.txt

I'd use sed:

sed -ns 7,11p /source/path/*.txt >/path/to/results.txt

hard to get much more concise than that with any common tool

But you do have to learn sed. Avoiding that is precisely why I stick
with Python.

+1 [cross-platform] QOTW