diff --git a/dataframe.go b/dataframe.go
index ff61dbfeec9c86f0357f5a2df37f1ceba8a87e93..2f7d827969f31dabc40c61b138a22d0771e47972 100644
--- a/dataframe.go
+++ b/dataframe.go
@@ -228,28 +228,6 @@ func (df DataFrame) print(
 	return str
 }
 
-// Subset returns a subset of the rows of the original DataFrame based on the
-// Series subsetting indexes.
-func (df DataFrame) Subset(start, end int) DataFrame {
-	if df.Err != nil {
-		return df
-	}
-	columns := make([]Series, df.ncols)
-	for i, column := range df.columns {
-		s := column.Subset(start, end)
-		columns[i] = s
-	}
-	nrows, ncols, err := checkColumnsDimensions(columns...)
-	if err != nil {
-		return DataFrame{Err: err}
-	}
-	return DataFrame{
-		columns: columns,
-		ncols:   ncols,
-		nrows:   nrows,
-	}
-}
-
 func checkColumnsDimensions(se ...Series) (nrows, ncols int, err error) {
 	ncols = len(se)
 	nrows = -1
diff --git a/dataframe_subset.go b/dataframe_subset.go
new file mode 100644
index 0000000000000000000000000000000000000000..ea0b0d98502932007e0ef7cf41c87db7414d2d57
--- /dev/null
+++ b/dataframe_subset.go
@@ -0,0 +1,23 @@
+package pandas
+
+// Subset returns a subset of the rows of the original DataFrame based on the
+// Series subsetting indexes.
+func (df DataFrame) Subset(start, end int) DataFrame {
+	if df.Err != nil {
+		return df
+	}
+	columns := make([]Series, df.ncols)
+	for i, column := range df.columns {
+		s := column.Subset(start, end)
+		columns[i] = s
+	}
+	nrows, ncols, err := checkColumnsDimensions(columns...)
+	if err != nil {
+		return DataFrame{Err: err}
+	}
+	return DataFrame{
+		columns: columns,
+		ncols:   ncols,
+		nrows:   nrows,
+	}
+}