Hey guys,

I'm new to python so if this is a silly question, pardon me.

I have the following basic assignment:

Take a user-specified range of lines from some data file, call it input, and write them to an output data file. What I want to do is have the user specify the range (for example lines 10-20) that will be picked from the input file to the output file. I am trying to use readlines() and I am able to get the program to pick a certain number of lines, but it always begins as line 1. For example, if I specify lines (30-200) it will recognize that it must extract 170 lines from the input file; however, it starts at line 1 and runs to line 170 instead of starting at line 30. Here is a snipet of the code:

first = int(raw_input('Enter a starting value'))
last = int(raw_input('Enter a final value'))

def add_line_numbers(infile, outfile):
f = open(infile,'r')
o = open(outfile,'w')
i = 1


for i in range(first, last):
o.write(str(i)+'\t'+f.readline())


f.close()
o.close()


--- Parsing code follows


The code originally worked fine until I began editing it. The original code takes an entire input file and transfers it to an entire output file. So only my edits are in question.

The 'i' acts as a counter, and that part works fine. The counter will read 30-200 for example; however, the lines that are inputing are still 1-170 from the original data type.

As I said, I am new to python and very amenable to suggestions so if you have a smarter way to tackled this problem, I am all ears.

This has been a very frustrating process. I'd appreciate help so much.

You read it one line at a time, but write only if the counter is between the numbers. And don't use "i", "l", or "o" as single variables because they look too much like numbers.

Thanks very much for your help.

There's always a more clever way :-)