Module `hub.util.slice`

Expand source code

def merge_slices(existing_slice: slice, new_slice: slice) -> slice:
    """Compose two slice objects

    Given an iterable x, the following should be equivalent:
    x[existing_slice][new_slice]
    x[merge_slices(existing_slice, new_slice)]

    Args:
        existing_slice (slice): The existing slice to be restricted.
        new_slice (slice): The new slice to be applied to the existing slice.

    Returns:
        slice: the composition of the given slices
    """

    # Combine the steps
    step1 = existing_slice.step if existing_slice.step is not None else 1
    step2 = new_slice.step if new_slice.step is not None else 1
    step = step1 * step2

    # Combine the start points
    start1 = existing_slice.start if existing_slice.start is not None else 0
    start2 = new_slice.start if new_slice.start is not None else 0
    start = start1 + start2 * step1

    # Combine the end points
    stop1 = existing_slice.stop
    stop2 = new_slice.stop

    if stop2 is None:
        stop = stop1
    else:
        stop = start + (stop2 - start2) * step1
        if stop1 is not None:
            stop = min(stop, stop1)

    return slice(start, stop, step)

Functions

def merge_slices(existing_slice: slice, new_slice: slice) ‑> slice

Compose two slice objects

Given an iterable x, the following should be equivalent: x[existing_slice][new_slice] x[merge_slices(existing_slice, new_slice)]

Args

existing_slice : slice: The existing slice to be restricted.
new_slice : slice: The new slice to be applied to the existing slice.

Returns

slice: the composition of the given slices

Expand source code

def merge_slices(existing_slice: slice, new_slice: slice) -> slice:
    """Compose two slice objects

    Given an iterable x, the following should be equivalent:
    x[existing_slice][new_slice]
    x[merge_slices(existing_slice, new_slice)]

    Args:
        existing_slice (slice): The existing slice to be restricted.
        new_slice (slice): The new slice to be applied to the existing slice.

    Returns:
        slice: the composition of the given slices
    """

    # Combine the steps
    step1 = existing_slice.step if existing_slice.step is not None else 1
    step2 = new_slice.step if new_slice.step is not None else 1
    step = step1 * step2

    # Combine the start points
    start1 = existing_slice.start if existing_slice.start is not None else 0
    start2 = new_slice.start if new_slice.start is not None else 0
    start = start1 + start2 * step1

    # Combine the end points
    stop1 = existing_slice.stop
    stop2 = new_slice.stop

    if stop2 is None:
        stop = stop1
    else:
        stop = start + (stop2 - start2) * step1
        if stop1 is not None:
            stop = min(stop, stop1)

    return slice(start, stop, step)