def seqids(args):
    p = OptionParser(seqids.__doc__)
    p.add_option("--maxn", default=100, type="int",
                 help="Maximum number of seqids")
    p.add_option("--prefix", help="Seqids must start with")
    p.add_option("--exclude", default="random", help="Seqids should not contain")
    opts, args = p.parse_args(args)

    if len(args) < 1:
        sys.exit(not p.print_help())

    bedfile, = args
    pf = opts.prefix
    exclude = opts.exclude
    bed = Bed(bedfile)
    s = bed.seqids
    if pf:
        s = [x for x in s if x.startswith(pf)]
    if exclude:
        s = [x for x in s if not exclude in x]
    s = s[:opts.maxn]
    print ",".join(s)
%prog seqids bedfile
dataset/ETHPy150Open tanghaibao/jcvi/formats/bed.py/seqids