Added more drop tests for table types.

Project.toml

@@ -4,7 +4,9 @@ authors = ["Invenia Technical Computing"]
 version = "0.2.0"
 
 [deps]
+DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
 IterTools = "c8e1da08-722c-5040-9ed9-7db0dc04731e"
+Missings = "e1d29d7a-bbdc-5cf2-9ac0-f12de2c33e28"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 StatsBase = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"

src/imputors/drop.jl

@@ -21,6 +21,9 @@ julia> impute(M, DropObs(; context=Context(; limit=1.0)); dims=2)
  1.0  2.0  5.0
  1.1  2.2  5.5
 ```
+
+WARNING: Observations can only be removed in-place for some input data types others
+(e.g., matrices, array views, some tables) will require a copy/collect.
 """
 struct DropObs <: Imputor
     context::AbstractContext
@@ -30,23 +33,25 @@ end
 DropObs(; context=Context()) = DropObs(context)
 
 function impute!(data::AbstractVector, imp::DropObs)
+    parent(data) === data || return impute!(parent(data), imp)
+
     imp.context() do c
         filter!(x -> !ismissing(c, x), data)
     end
+
+    return data
 end
 
 function impute!(data::AbstractMatrix, imp::DropObs; dims=1)
+    # parent(data) === data || return impute!(parent(data), imp)
+
     imp.context() do c
         return filterobs(data; dims=dims) do obs
             !ismissing(c, obs)
         end
     end
 end
 
-# Deleting elements from subarrays doesn't work so we need to collect that data into
-# a separate array.
-impute!(data::SubArray, imp::DropObs) = impute!(collect(data), imp::DropObs)
-
 function impute!(table, imp::DropObs)
     imp.context() do c
         @assert istable(table)
@@ -88,6 +93,8 @@ julia> impute(M, DropVars(; context=Context(; limit=0.2)); dims=2)
 1×5 Array{Union{Missing, Float64},2}:
  1.1  2.2  3.3  missing  5.5
 ```
+
+WARNING: Variables cannot be removed in-place, so this method will internally perform a copy.
 """
 struct DropVars <: Imputor
     context::AbstractContext
@@ -97,20 +104,11 @@ end
 DropVars(; context=Context()) = DropVars(context)
 
 function impute!(data::AbstractMatrix, imp::DropVars; dims=1)
-    return filtervars(data; dims=dims) do var
-        try
-            imp.context() do c
-                for x in var
-                    ismissing(c, x)
-                end
-            end
-            return true
-        catch e
-            if isa(e, ImputeError)
-                return false
-            else
-                rethrow(e)
-            end
+    # parent(data) === data || return impute!(parent(data), imp)
+
+    imp.context() do c
+        return filtervars(data; dims=dims) do vars
+            !ismissing(c, vars)
         end
     end
 end
@@ -119,25 +117,13 @@ function impute!(table, imp::DropVars)
     istable(table) || throw(MethodError(impute!, (table, imp)))
     cols = Tables.columns(table)
 
-    cnames = Iterators.filter(propertynames(cols)) do cname
-        try
-            imp.context() do c
-                col = getproperty(cols, cname)
-                for i in eachindex(col)
-                    ismissing(c, col[i])
-                end
-            end
-            return true
-        catch e
-            if isa(e, ImputeError)
-                return false
-            else
-                rethrow(e)
-            end
+    imp.context() do c
+        cnames = Iterators.filter(propertynames(cols)) do cname
+            !ismissing(c, getproperty(cols, cname))
         end
-    end
 
-    selected = Tables.select(table, cnames...)
-    table = materializer(table)(selected)
-    return table
+        selected = Tables.select(table, cnames...)
+        table = materializer(table)(selected)
+        return table
+    end
 end