In this recipe, we will explain in detail how the Dict
and Set
types identify keys in Julia.
The example that we will use is the creation of a dictionary that stores a preimage
function.
Given a function,
and
, we will call preimage
of
a set
; see the example at http://mathworld.wolfram.com/Preimage.html.
In particular, we need to create preimage
of all possible values of a mapping,
, given the domain,
and the set B defined as an image of A under
, as calculated by Julia.
Note
In the GitHub repository for this recipe, you will find the commands.txt
file that contains the presented sequence of shell and Julia commands.
Now open your favorite terminal to execute commands.