How to assign boundary conditions based on values of dolfinx.Function

dolfinx
2

How about using a UFL conditional (Form language — Unified Form Language (UFL) 2021.1.0 documentation)
i.e.

v = Function(V)
# Assign values 1 and 2 to v
# ...
# Add boundary condition terms to variational form
F += ufl.conditional(ufl.eq(v, 1), 1, 0) *  robin integrand * ds 
F += ufl.conditional(ufl.eq(v, 2), 1, 0) * neumann_integrand * ds
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