Fill existing arrays with scalars

src/dataframe/dataframe.jl

@@ -365,10 +365,13 @@ function Base.setindex!(df::DataFrame,
 end
 
 # df[SingleColumnIndex] = Single Item (EXPANDS TO NROW(DF) if NCOL(DF) > 0)
-function Base.setindex!(df::DataFrame,
-                v::Any,
-                col_ind::ColumnIndex)
-    insert_single_column!(df, upgrade_scalar(df, v), col_ind)
+function Base.setindex!(df::DataFrame, v, col_ind::ColumnIndex)
+    if haskey(index(df), col_ind)
+        j = index(df)[col_ind]
+        fill!(df.columns[j], v)
+    else
+        insert_single_column!(df, upgrade_scalar(df, v), col_ind)
+    end
 end
 
 # df[MultiColumnIndex] = DataFrame
@@ -397,7 +400,7 @@ function Base.setindex!{T <: ColumnIndex}(df::DataFrame,
                                   col_inds::AbstractVector{T})
     dv = upgrade_vector(v)
     for col_ind in col_inds
-        insert_single_column!(df, dv, col_ind)
+        df[col_ind] = dv
     end
     return df
 end
@@ -406,14 +409,13 @@ end
 function Base.setindex!(df::DataFrame,
                 val::Any,
                 col_inds::AbstractVector{Bool})
-    setindex!(df, val, find(col_inds))
+    df[find(col_inds)] = val
 end
 function Base.setindex!{T <: ColumnIndex}(df::DataFrame,
                                   val::Any,
                                   col_inds::AbstractVector{T})
-    dv = upgrade_scalar(df, val)
     for col_ind in col_inds
-        insert_single_column!(df, dv, col_ind)
+        df[col_ind] = val
     end
     return df
 end

test/mutation.jl

@@ -0,0 +1,9 @@
+module TestMutation
+    using Base.Test, DataFrames
+
+    # columns should not alias if scalar broadcasted
+    df = DataFrame(A=[0],B=[0])
+    df[1:end] = 0.0
+    df[1,:A] = 1.0
+    @test df[1,:B] === 0
+end

test/runtests.jl

@@ -28,7 +28,8 @@ my_tests = ["utils.jl",
             "duplicates.jl",
             "show.jl",
             "statsmodel.jl",
-            "contrasts.jl"]
+            "contrasts.jl",
+            "mutation.jl"]
 
 println("Running tests:")