Merge pull request #29 from alan-turing-institute/isrepresented

Add isrepresented method (version of `in` for MLJTypes)

Author: ablaom

src/MLJModelInterface.jl

@@ -38,7 +38,7 @@ export matrix, int, classes, decoder, table,
        nrows, selectrows, selectcols, select
 
 # equality
-export is_same_except
+export is_same_except, isrepresented
 
 # re-exports from ScientificTypes
 export Scientific, Found, Unknown, Known, Finite, Infinite,

src/equality.jl

@@ -61,3 +61,24 @@ end
 Base.in(x::MLJType, itr::Set) = special_in(x, itr)
 Base.in(x::MLJType, itr::AbstractVector) = special_in(x, itr)
 Base.in(x::MLJType, itr::Tuple) = special_in(x, itr)
+
+# A version of `in` that actually uses `==`:
+
+"""
+    isrepresented(object::MLJType, objects)
+
+Test if `object` has a representative in the iterable
+`objects`. This is a weaker requirement than `object in objects`.
+
+Here we say `m1` *respresents* `m2` if `is_same_except(m1, m2)` is
+`true`.
+
+"""
+isrepresented(object::MLJType, ::Nothing) = false
+function isrepresented(object::MLJType, itr)::Union{Bool,Missing}
+    for m in itr
+        ismissing(m) && return missing
+        is_same_except(m, object) && return true
+    end
+    return false
+end

test/equality.jl

@@ -84,4 +84,17 @@ end
 
 end
 
+@testset "isrepresented" begin
+    m = Foo(MersenneTwister(7), 1, 2)
+    m2 = Foo(MersenneTwister(8), 1, 2)
+    n = Foo(MersenneTwister(7), 3, 2)
+    p = Foo(MersenneTwister(9), 4, 5)
+    models = [m, n]
+
+    @test isrepresented(m, nothing) == false
+    @test isrepresented(m, models)
+    @test isrepresented(m2, models)
+    @test !isrepresented(p, models)
+end
+
 true