narrowed_data_id

function of dascore.utils.identity

source

narrowed_data_id(
    attrs ,
    before: ‘ArraySource | None’ ,
    after: ‘ArraySource | None’ ,
    coords = None,
    new_coords = None,
)-> ‘str | None’

Return the id of a window of the array a patch already is, or None.

A patch nothing has been done to is its source, so narrowing it to something the source can still load names a window of the same array rather than the result of an operation. Windows compose, so which selections led there does not matter.

Parameters

Parameter	Description
attrs	The attrs of the patch being narrowed.
before	The source of that patch, if it has one.
after	The source the narrowed patch would load from, if any.
coords, new_coords	The coordinates before and after the narrowing. A source states a dimensional window and nothing else, so without them, or when anything outside that window moved, there is no window to name.

Returns

The window’s id, or None when the result must be derived as usual: the patch is no longer what its source loads (anything was done to it), or one of the two describes no array (a stepped, fancy or non-contiguous selection detaches the source).