I've created a data structure that is a hash of arrays with a special property: the hash keeps track of the combined order in which items are appended to its arrays. For example (pseudocode):h = HashOfArray()h[a].append(1) // accessing an unset key returns an empty arrayh[b].append(2)h[a].append(3)h[b].append(4)h[a]>>> [1, 3]h[b]>>> [2, 4]h.items()>>> [1, 2, 3, 4]I'm struggling with coming up with a good name for this data structure. Does it have a commonly used name? I've called it HashOfArray but that fails to convey its main property: that it maintains the combined append order of the arrays.Example implementation in Ruby:https://gist.github.com/kajic/7981533
What is this hash of array data structure called?
data structures;arrays;hash tables