Bijections

Overview

Mathematically, a bijection is a one-to-one and onto function between sets. In this module, we provide the Bijection data type that represents a bijection between finite collections of objects.

A Dict in Julia is not one-to-one. Two different keys might have the same value. A Bijection data structure behaves just like a Dict except that it prevents assigning the same value to two different keys.

Getting started

After using Bijections we create a new Bijection in one of the following ways:

• b = Bijection(): This gives a new Bijection in which the keys and values are of Any type.

• b = Bijection{S,T}(): This gives a new Bijection in which the keys are of type S and the values are of type T.

• b = Bijection(x,y): This gives a new Bijection in which the keys are type typeof(x), the values are type typeof(y) and the key-value pair (x,y) is inserted into the Bijection.

• b = Bijection(dict::AbstractDict{S, T}): This gives a new Bijection in which the keys are type S, the values are type T and all key-value pairs in dict are inserted into the Bijection.

• b = Bijection(pair_list::Vector{Pair{S, T}}): Create a new Bijection using a list of pairs.

See also the Mutable Objects page for additional constructor options.