Merge pull request #4 from J-F-Liu/master

Add transpose() method

src/lib.rs

@@ -624,6 +624,21 @@ impl<T: Clone> Grid<T> {
     pub fn into_vec(self) -> Vec<T> {
         self.data
     }
+
+    /// Transpose the grid so that columns become rows in new grid.
+    pub fn transpose(&self) -> Grid<T> {
+        let mut data = Vec::with_capacity(self.data.len());
+        for c in 0..self.cols {
+            for r in 0..self.rows {
+                data.push(self[r][c].clone());
+            }
+        }
+        Grid {
+            data,
+            cols: self.rows,
+            rows: self.cols,
+        }
+    }
 }
 
 impl<T: Clone> Clone for Grid<T> {
@@ -1126,4 +1141,10 @@ mod test {
         let grid = Grid::init(1, 2, 3);
         assert_eq!(grid.size(), (1, 2));
     }
+
+    #[test]
+    fn transpose() {
+        let grid: Grid<u8> = grid![[1,2,3][4,5,6]];
+        assert_eq!(format!("{:?}", grid.transpose()), "[[1, 4][2, 5][3, 6]]");
+    }
 }