Convert integers to condensed list of strings and back

IntegerExamples.py

#!/usr/bin/env python


def getMachine():
    """Determine the name of the machine this process is running on."""
    from socket import gethostname
    return gethostname()


def splitArgs(optArgs, sysArgs, options=None):
    try:
        index = sysArgs.index("--")
        comArgs = sysArgs[index+1:]
    except ValueError:
        index = -1
        comArgs = []
        runArgs = optArgs

    if index > 0:
        runArgs = optArgs[:-1*len(comArgs)]
        temp = " "
        comArgs = temp.join(comArgs)
    else:
        comArgs = ""
    runs = generateList(runArgs, options)
    if options is not None:
        if options.verbose is True or int(options.verbose) > 0:
            print "RUNS:", runs
            print "COM :", comArgs
    return (runs, comArgs)


def getConcurrentIndices(runs, startIndex=0):
    """Compress a collection of consecutive integers into a single string
    with a dash in the middle"""
    start = startIndex
    stop = start
    for i in range(startIndex, len(runs)-1):
        if runs[i]+1 == runs[i+1]:
            stop = i+1
        else:
            return (start, stop)
    return (start, stop)


def condenseList(runs):
    """Turn a list of integers into a condensed string version of the list"""
    result = []
    (start, stop) = (0, 0)
    length = len(runs)
    while stop < length:
        (start, stop) = getConcurrentIndices(runs, start)
        if stop >= length:
            break
        if start < stop:
            result.append("%s-%s" % (runs[start], runs[stop]))
        else:
            result.append(runs[start])
        start = stop+1

    # convert the remaining runs into strings
    result = map(lambda x: str(x), result)

    return ",".join(result)


def generateList(args, options=None):
    """Convert a string list into a list of integers

    args = single string or list of strings in the form
        '\d+(-\d+)?(,\d+(-\d+)?)*'
        For example: '12-15,30-33'
    options = If options.verbose exists and is True, then this function
              will send a warning message to stdout when it cannot
              understand a portion of args.

    Returns a list of all the integers indicated by args.  The example
    above would return the list [12, 13, 14, 15, 30, 31, 32, 33].
    Returned integers will be sorted least to greatest with no
    duplicates.
    """
    optargs = getattr(options, 'run', None)
    if args is None:
        args = []
    if optargs is not None:
        args.append(optargs)
    if len(args) <= 0:
        raise RuntimeError("Cannot generate list from empty")
    verbose = getattr(options, 'verbose', False)
    # normalize args to always be a list
    if (not isinstance(args, list)):
        args = [args]
    # args should be a list of strings like this:
    # ['1-5,10', '12,15-21'].
    # force all elements to be strings and split on commas
    args = [str(a).split(',') for a in args]
    # args should now be a list of lists like this:
    # [['1-5', '10'], ['12', '15-21']]
    # flatten the list back out again
    from operator import add   # function equivalent of +
    args = reduce(add, args)
    # args should now be a list of strings again like this:
    # ['1-5', '10', '12', '15-21']
    # use a set instead of a list so overlapping ranges won't create
    # duplicate integers in the output
    result = set()
    for a in args:
        # watch for badly formatted input ranges
        # Mainly I expect the int() cast below to fail for bad input.
        try:
            ends = [int(x) for x in a.split('-')]
            if (len(ends) > 2):
                raise ValueError("too many dashes")
            # reverse any backwards ranges
            ends.sort()
            result |= set(xrange(ends[0], ends[-1] + 1))
        except:
            if verbose:
                print "WARN: Skipping range \"%s\"" % a
    return sorted(result)


######################################################################
# MAIN FUNCTION FOR TESTING
######################################################################
if __name__ == "__main__":
    print "getMachine():", getMachine()
    print "condenseList([1,2,3,7])", condenseList([1, 2, 3, 7])
    print "generateList('1-3,8')", generateList("1-3,8")