indices2slices.py

def indices2slices(indices):
    """
    convert a list of discrete indices into a minimal list of slices
    :returns: [(start1:stop1:step1), (start2:stop2:step2) ...)]
    """
    slices = []
    if len(indices) == 1:
        slices = [indices[0]]
    elif len(indices) > 1:
        start, stop, step = (indices[0], None, None)
        for idx, value in enumerate(indices[1:]):
            span = value - indices[idx]
            if step and span != step:
                slices.append((start, stop, None if step == 1 else step,))
                start, stop, step = (value, value, None)
            else:
                start, stop, step = (start, value, span)
        slices.append((start, stop, None if step == 1 else step,))
    return slices