[Tutor] Performing an union of two files containing keywords

[Oscar Benjamin]

On 17 February 2014 09:07, Aaron Misquith <aaronmisquith at gmail.com> wrote:
>
> The program that i'm working on just combines two files. Any help on
> performing an union such that a keyword would not be repeated would be
> appreciated.
>
> Code:
> with open("C:\\File1.txt") as fin1: lines = fin1.readlines()
> with open("C:\\File2.txt") as fin2: lines.extend(fin2.readlines())
> with open("D:\\file3.txt", "r+") as fout: fout.write('\n'.join(lines))

Something like this:

with open(r'D:\file3.txt', 'r+') as fout:
    keywords_seen = set()
    for filename in r'C:\File1.txt', r'C:\File2.txt':
        with open(filename) as fin:
            for line in fin:
                keyword = line.strip()
                if keyword not in keywords_seen:
                    fout.write(line)
                    keywords.add(keyword)

Why are you opening the output file with mode 'r+'? Are you intending
to only overwrite part of the file? I think you probably should use
mode 'w' instead.


Oscar