Source code for holoviews.core.traversal

"""
Advanced utilities for traversing nesting/hierarchical Dimensioned
objects either to inspect the structure of their declared dimensions
or mutate the matching elements.
"""

from collections import defaultdict
from operator import itemgetter

from .dimension import Dimension
from .util import merge_dimensions, cartesian_product

try:
    import itertools.izip as zip
except ImportError:
    pass


def create_ndkey(length, indexes, values):
    key = [None] * length
    for i, v in zip(indexes, values):
        key[i] = v
    return tuple(key)

[docs]def uniform(obj): """ Finds all common dimension keys in the object including subsets of dimensions. If there are is no common subset of dimensions, None is returned. """ from .spaces import HoloMap dim_groups = obj.traverse(lambda x: tuple(x.kdims), (HoloMap,)) if dim_groups: dgroups = [frozenset(d.name for d in dg) for dg in dim_groups] return all(g1 <= g2 or g1 >= g2 for g1 in dgroups for g2 in dgroups) return True
[docs]def unique_dimkeys(obj, default_dim='Frame'): """ Finds all common dimension keys in the object including subsets of dimensions. If there are is no common subset of dimensions, None is returned. Returns the list of dimensions followed by the list of unique keys. """ from .ndmapping import NdMapping, item_check from .spaces import HoloMap key_dims = obj.traverse(lambda x: (tuple(x.kdims), list(x.data.keys())), (HoloMap,)) if not key_dims: return [Dimension(default_dim)], [(0,)] dim_groups, keys = zip(*sorted(key_dims, key=lambda x: -len(x[0]))) dgroups = [frozenset(d.name for d in dg) for dg in dim_groups] subset = all(g1 <= g2 or g1 >= g2 for g1 in dgroups for g2 in dgroups) # Find unique keys if subset: dims = merge_dimensions(dim_groups) all_dims = sorted(dims, key=lambda x: dim_groups[0].index(x)) else: # Handle condition when HoloMap/DynamicMap dimensions do not overlap hmaps = obj.traverse(lambda x: x, ['HoloMap']) if hmaps: raise ValueError('When combining HoloMaps into a composite plot ' 'their dimensions must be subsets of each other.') dimensions = merge_dimensions(dim_groups) dim_keys = {} for dims, keys in key_dims: for key in keys: for d, k in zip(dims, key): dim_keys[d.name] = k if dim_keys: keys = [tuple(dim_keys.get(dim.name) for dim in dimensions)] else: keys = [] return merge_dimensions(dim_groups), keys ndims = len(all_dims) unique_keys = [] for group, keys in zip(dim_groups, keys): dim_idxs = [all_dims.index(dim) for dim in group] for key in keys: padded_key = create_ndkey(ndims, dim_idxs, key) matches = [item for item in unique_keys if padded_key == tuple(k if k is None else i for i, k in zip(item, padded_key))] if not matches: unique_keys.append(padded_key) # Add cartesian product of DynamicMap values to keys values = [d.values for d in all_dims] if obj.traverse(lambda x: x, ['DynamicMap']) and values and all(values): unique_keys += list(zip(*cartesian_product(values))) with item_check(False): sorted_keys = NdMapping({key: None for key in unique_keys}, kdims=all_dims).data.keys() return all_dims, list(sorted_keys)
def bijective(keys): ndims = len(keys[0]) if ndims <= 1: return True for idx in range(ndims): getter = itemgetter(*(i for i in range(ndims) if i != idx)) store = [] for key in keys: subkey = getter(key) if subkey in store: return False store.append(subkey) return True
[docs]def hierarchical(keys): """ Iterates over dimension values in keys, taking two sets of dimension values at a time to determine whether two consecutive dimensions have a one-to-many relationship. If they do a mapping between the first and second dimension values is returned. Returns a list of n-1 mappings, between consecutive dimensions. """ ndims = len(keys[0]) if ndims <= 1: return True dim_vals = list(zip(*keys)) combinations = (zip(*dim_vals[i:i+2]) for i in range(ndims-1)) hierarchies = [] for combination in combinations: hierarchy = True store1 = defaultdict(list) store2 = defaultdict(list) for v1, v2 in combination: if v2 not in store2[v1]: store2[v1].append(v2) previous = store1[v2] if previous and previous[0] != v1: hierarchy = False break if v1 not in store1[v2]: store1[v2].append(v1) hierarchies.append(store2 if hierarchy else {}) return hierarchies