[Tutor] Omitting lines matching a list of strings from a file

[galaxywatcher at gmail.com]

>>  One formatting detail: there is a blank line after each line  
>> printed, how do I ged rid of the extra blank lines?

> lines = [line.strip() for line in infile if line[146:148] not in  
> omit_states]
> print '\n'.join(lines)

This approach stripped leading blank spaces introducing errors into my  
fixed width file.

> or alternatively
>
> lines = [line for line in infile if line[146:148] not in omit_states]
> print ''.join(lines)

This works beautifully leaving leading blank spaces intact. Thanks.

> Just remember that doing a list comprehension like that on a large  
> file will drastically reduce the speed of your application as well  
> as introduce memory bloat.

Processing a file with well over 1 million records worked very  
quickly, several seconds. Did not notice excessive memory bloat. I do  
have 2 gigs of ram on my Macbook  Pro however.