The title sums it up. I have seen some mentions in the RatFun and SpectralMeasures package but I am mostly looking for a function analogous to the ones found in the Sympy module for Python.
Edit: Thanks everyone for your answers and comments. I was looking for the discrete version of a dirac delta. At first I was confused and wanted to look for a "function" but I actually was just looking for the Kronecker delta which exhibits the following behavior:
delta(x) = 1 if x=0
delta(x) = 0 otherwise
I quickly realized that I didn't even need a function, I just had to take care of the differences in the argument. Thanks again!
The OP basically wants the Kronecker delta function [https://en.wikipedia.org/wiki/Kronecker_delta] which is trivial in julia:
delta(n) = n == 0