Python: find closest key in a dictionary from the given input key

Question

I have a data in form a dictionary.. NOw I take the input from the user and it can be anything.. And I am trying to do the following. If the key exists then cool.. fetch the

Answer 1

Using sortedcontainers.SortedDict, you can do this like this:

def closest_item(sdict, key):
    if len(sdict) == 0:
        raise KeyError('No items in {sdict.__class__.__name__}')

    if len(sdict) == 1:
        return next(iter(sdict.items()))

    idx_before = next(sdict.irange(minimum=key), None)
    idx_after = next(sdict.irange(maximum=key, reverse=True), None)

    if idx_before is None:
        idx = idx_after

    elif idx_after is None:
        idx = idx_before
    else:
        idx = min(idx_before, idx_after, key=lambda x: abs(x - key))

    return idx, sdict[idx]