This code is written to import a file, start to read the lines after a particular line and stop on a particular line. Finally results are converted to float numbers and written in a file.

file_refiner.py

'''
File Refiner
May 18 2015

This code is written to import a file, start to read the lines after a particular line 
and stop on a particular line. Finally results will convert to float number and write 
in a file.

Assuming the code and file.crd are in the same directory, and we want to miss first 5 lines
and extract 239 lines after that, one should type:

> Python file.crd 5 239 

results in file.crd_refined in the same directory.

-- Mahdi Sadjadi --

'''

import csv,sys
 
imported_file = sys.argv[1]

starting_line = eval(sys.argv[2]) # number of lines that one needs to skip
required_coordinates = eval(sys.argv[3]) # number of required lines from the file
ending_line = starting_line + required_coordinates + 1 # last line to be returned

f = open(imported_file,"r") # importing the original file
g = open(imported_file+"_refined","w") # exporting the refined file

linesCounter = 1

for line in f:
    if linesCounter > starting_line and linesCounter < ending_line:
        numbers = map(float,line.split()) # converting to float
        writer = csv.writer(g, delimiter=' ') # setting the delimiter 
        writer.writerow(map("{0:0.6f}".format,numbers)) # setting precision of exported numbers
    linesCounter += 1
         
f.close()
g.close()