Merge pull request #2363 from andrewrosemberg/ar/has_variable

Define haskey for JuMP AbstractModel

src/JuMP.jl

@@ -954,6 +954,15 @@ function Base.setindex!(m::JuMP.Model, value, name::Symbol)
     m.obj_dict[name] = value
 end
 
+"""
+    haskey(model::AbstractModel, name::Symbol)
+
+Determine whether the model has a mapping for a given name.
+"""
+function Base.haskey(model::AbstractModel, name::Symbol)
+    return haskey(object_dictionary(model), name)
+end
+
 """
     operator_warn(model::AbstractModel)
     operator_warn(model::Model)

test/model.jl

@@ -492,6 +492,13 @@ function test_copy_direct_mode()
     @test_throws ErrorException JuMP.copy(model)
 end
 
+function test_haskey()
+    model = Model()
+    @variable(model, p[i=1:10] >=  0)
+    @test haskey(model, :p)
+    @test !haskey(model, :i)
+end
+
 function runtests()
     for name in names(@__MODULE__; all = true)
         if !startswith("$(name)", "test_")