vwoptimize.py 文件源码

def open_anything(source, format, ignoreheader, force_unbuffered=False):
    source = open_regular_or_compressed(source)

    if force_unbuffered:
        # simply disabling buffering is not enough, see this for details: http://stackoverflow.com/a/6556862
        source = iter(source.readline, '')

    if format == 'vw':
        return source

    if format == 'tsv':
        reader = csv.reader(source, csv.excel_tab)
        if ignoreheader:
            reader.next()
    elif format == 'csv':
        reader = csv.reader(source, csv.excel)
        if ignoreheader:
            reader.next()
    else:
        raise ValueError('format not supported: %s' % format)

    return reader