javascriptdata · risenW · Feb 20, 2022 · Jan 12, 2022 · Jan 16, 2022 · Jan 19, 2022
diff --git a/src/danfojs-base/core/frame.ts b/src/danfojs-base/core/frame.ts
@@ -525,12 +525,16 @@ export default class DataFrame extends NDframe implements DataFrameInterface {
       * ```
     */
     head(rows: number = 5): DataFrame {
-        if (rows > this.shape[0]) {
-            throw new Error("ParamError: Number of rows cannot be greater than available rows in data")
-        }
+
         if (rows <= 0) {
             throw new Error("ParamError: Number of rows cannot be less than 1")
         }
+        if (this.shape[0] <= rows) {
+            return this.copy()
+        }
+        if (this.shape[0] - rows < 0) {
+            throw new Error("ParamError: Number of rows cannot be greater than available rows in data")
+        }
 
         return this.iloc({ rows: [`0:${rows}`] })
     }
@@ -545,12 +549,17 @@ export default class DataFrame extends NDframe implements DataFrameInterface {
       * ```
     */
     tail(rows: number = 5): any {
-        if (rows > this.shape[0]) {
-            throw new Error("ParamError: Number of rows cannot be greater than available rows in data")
-        }
+
         if (rows <= 0) {
             throw new Error("ParamError: Number of rows cannot be less than 1")
         }
+        if (this.shape[0] <= rows) {
+            return this.copy()
+        }
+        if (this.shape[0] - rows < 0) {
+            throw new Error("ParamError: Number of rows cannot be greater than available rows in data")
+        }
+
         rows = this.shape[0] - rows
         return this.iloc({ rows: [`${rows}:`] })
     }

diff --git a/src/danfojs-base/core/series.ts b/src/danfojs-base/core/series.ts
@@ -162,6 +162,15 @@ export default class Series extends NDframe implements SeriesInterface {
       * ```
     */
     head(rows: number = 5): Series {
+        if (rows <= 0) {
+            throw new Error("ParamError: Number of rows cannot be less than 1")
+        }
+        if (this.shape[0] <= rows) {
+            return this.copy()
+        }
+        if (this.shape[0] - rows < 0) {
+            throw new Error("ParamError: Number of rows cannot be greater than available rows in data")
+        }
         return this.iloc([`0:${rows}`])
     }
 
@@ -176,6 +185,16 @@ export default class Series extends NDframe implements SeriesInterface {
       * ```
     */
     tail(rows: number = 5): Series {
+        if (rows <= 0) {
+            throw new Error("ParamError: Number of rows cannot be less than 1")
+        }
+        if (this.shape[0] <= rows) {
+            return this.copy()
+        }
+        if (this.shape[0] - rows < 0) {
+            throw new Error("ParamError: Number of rows cannot be greater than available rows in data")
+        }
+
         const startIdx = this.shape[0] - rows
         return this.iloc([`${startIdx}:`])
     }

diff --git a/src/danfojs-base/shared/utils.ts b/src/danfojs-base/shared/utils.ts
@@ -334,7 +334,8 @@ export default class Utils {
         if (
             typeof arr[0] == "number" ||
             typeof arr[0] == "string" ||
-            typeof arr[0] == "boolean"
+            typeof arr[0] == "boolean" ||
+            arr[0] === null
         ) {
             return true;
         } else {

diff --git a/src/danfojs-browser/tests/core/frame.test.js b/src/danfojs-browser/tests/core/frame.test.js
@@ -304,19 +304,19 @@ describe("DataFrame", function () {
       const df = new dfd.DataFrame(data, { columns: cols });
       assert.deepEqual(df.head(2).values, [ [ 1, 2, 3 ], [ 4, 5, 6 ] ]);
     });
-    it("Throws error if row specified is greater than values", function () {
+    it("Throws error if row specified is less than 0", function () {
       const data = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 20, 30, 40 ], [ 39, 89, 78 ] ];
       const cols = [ "A", "B", "C" ];
       const df = new dfd.DataFrame(data, { columns: cols });
-      assert.throws(() => df.head(10), Error,
-        "ParamError: Number of rows cannot be greater than available rows in data");
+      assert.throws(() => df.head(-1), Error,
+        "ParamError: Number of rows cannot be less than 1");
     });
-    it("Throws error if row specified is less than 0", function () {
+
+    it("Returns all rows when size of DataFrame is less than default (5)", function () {
       const data = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 20, 30, 40 ], [ 39, 89, 78 ] ];
       const cols = [ "A", "B", "C" ];
       const df = new dfd.DataFrame(data, { columns: cols });
-      assert.throws(() => df.head(-1), Error,
-        "ParamError: Number of rows cannot be less than 1");
+      assert.deepEqual(df.head().values, data);
     });
 
   });
@@ -328,13 +328,6 @@ describe("DataFrame", function () {
       const df = new dfd.DataFrame(data, { columns: cols });
       assert.deepEqual(df.tail(2).values, [ [ 20, 30, 40 ], [ 39, 89, 78 ] ]);
     });
-    it("Throws error if row specified is greater than values", function () {
-      const data = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 20, 30, 40 ], [ 39, 89, 78 ] ];
-      const cols = [ "A", "B", "C" ];
-      const df = new dfd.DataFrame(data, { columns: cols });
-      assert.throws(() => df.tail(10), Error,
-        "ParamError: Number of rows cannot be greater than available rows in data");
-    });
     it("Throws error if row specified is less than 0", function () {
       const data = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 20, 30, 40 ], [ 39, 89, 78 ] ];
       const cols = [ "A", "B", "C" ];
@@ -353,6 +346,12 @@ describe("DataFrame", function () {
       const df = new dfd.DataFrame(data);
       assert.deepEqual(df.tail(2).values, [ [ 1, 2, 34, 5, 0, 6, 4, 5, 6, 7 ], [ 20, 30, 40, 39, 89, 78, 45, 56, 56, 45 ] ]);
     });
+    it("Returns all rows when size of DataFrame is less than default (5)", function () {
+      const data = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 20, 30, 40 ], [ 39, 89, 78 ] ];
+      const cols = [ "A", "B", "C" ];
+      const df = new dfd.DataFrame(data, { columns: cols });
+      assert.deepEqual(df.tail().values, data);
+    });
   });
 
   describe("sample", function () {

diff --git a/src/danfojs-browser/tests/core/generic.test.js b/src/danfojs-browser/tests/core/generic.test.js
@@ -74,6 +74,19 @@ describe("Generic (NDFrame)", function () {
         "IndexError: Row index must contain unique values";
       });
     });
+
+    it("Successfully create a 2D Frame when first value is empty", function () {
+      let data = [ [ null, 20, 1 ], [ 20, 25, 3 ] ];
+      let ndframe = new dfd.NDframe({ data, isSeries: false });
+      //@ts-ignore
+      assert.deepEqual(ndframe.values, data);
+    });
+    it("Successfully create a 1D Frame when first value is empty", function () {
+      let data = [ null, 'bval2', 'bval3', 'bval4' ];
+      let ndframe = new dfd.NDframe({ data, isSeries: true });
+      //@ts-ignore
+      assert.deepEqual(ndframe.values, data);
+    });
   });
 
   describe("NDframe Created from JavaScript Object", function () {

diff --git a/src/danfojs-browser/tests/core/series.test.js b/src/danfojs-browser/tests/core/series.test.js
@@ -10,17 +10,16 @@ describe("Series Functions", () => {
       assert.deepEqual(sf.head(2).values, [ 1, 2 ]);
       assert.deepEqual(sf.head(5).values, [ 1, 2, 3, 4, 5 ]);
     });
-    it("throw error when row specified is greater than values", function () {
-      const data = [ "Boy", "Girl", "Man", "Woman", "Tall" ];
-      const cols = [ "Items" ];
-      const sf = new dfd.Series(data, { columns: cols });
-      assert.throws(function () { assert.deepEqual(sf.head(10).values, data); }, Error, `row slice [end] index cannot be bigger than 5`);
-    });
+    it("Returns all rows when DataFrame length is less than rows", function () {
+      const data = [ 1, 2, 5 ];
+      const sf = new dfd.Series(data);
+      assert.deepEqual(sf.head().values, data);
 
+    });
     it("throw error when row specified is less than 0", function () {
       const data = [ 1, 2, 3, 4, 5, 620, 30, 40, 39, 89, 78 ];
       const sf = new dfd.Series(data);
-      assert.throws(function () { assert.deepEqual(sf.head(-1).values, data); }, Error, `ParamError: end must be greater than start`);
+      assert.throws(function () { assert.deepEqual(sf.head(-1).values, data); }, Error, `ParamError: Number of rows cannot be less than 1`);
     });
   });
 
@@ -33,18 +32,17 @@ describe("Series Functions", () => {
       assert.deepEqual(sf.tail(4).values, [ 40, 39, 89, 78 ]);
 
     });
-    it("throw error when row specified is greater than values", function () {
-      const data = [ "Boy", "Girl", "Man", "Woman", "Tall" ];
-      const cols = [ "Items" ];
-      const sf = new dfd.Series(data, { columns: cols });
-      assert.throws(function () { assert.deepEqual(sf.tail(15).values, data); }, Error, `row slice [start] index cannot be less than 0`);
-    });
+    it("Returns all rows when DataFrame length is less than rows", function () {
+      const data = [ 1, 2, 5 ];
+      const sf = new dfd.Series(data);
+      assert.deepEqual(sf.tail().values, data);
 
+    });
     it("throw error when row specified is less than 0", function () {
       const data = [ "Boy", "Girl", "Man", "Woman", "Tall" ];
       const cols = [ "Items" ];
       const sf = new dfd.Series(data, { columns: cols });
-      assert.throws(function () { assert.deepEqual(sf.tail(-1).values, data); }, Error, `ParamError: end must be greater than start`);
+      assert.throws(function () { assert.deepEqual(sf.tail(-1).values, data); }, Error, `ParamError: Number of rows cannot be less than 1`);
     });
   });
 

diff --git a/src/danfojs-node/test/core/frame.test.ts b/src/danfojs-node/test/core/frame.test.ts
@@ -308,19 +308,18 @@ describe("DataFrame", function () {
             const df = new DataFrame(data, { columns: cols });
             assert.deepEqual(df.head(2).values, [[1, 2, 3], [4, 5, 6]]);
         });
-        it("Throws error if row specified is greater than values", function () {
+        it("Throws error if row specified is less than 0", function () {
             const data = [[1, 2, 3], [4, 5, 6], [20, 30, 40], [39, 89, 78]];
             const cols = ["A", "B", "C"];
             const df = new DataFrame(data, { columns: cols });
-            assert.throws(() => df.head(10), Error,
-                "ParamError: Number of rows cannot be greater than available rows in data");
+            assert.throws(() => df.head(-1), Error,
+                "ParamError: Number of rows cannot be less than 1");
         });
-        it("Throws error if row specified is less than 0", function () {
+        it("Returns all rows when size of DataFrame is less than default (5)", function () {
             const data = [[1, 2, 3], [4, 5, 6], [20, 30, 40], [39, 89, 78]];
             const cols = ["A", "B", "C"];
             const df = new DataFrame(data, { columns: cols });
-            assert.throws(() => df.head(-1), Error,
-                "ParamError: Number of rows cannot be less than 1");
+            assert.deepEqual(df.head().values, data);
         });
 
     });
@@ -332,13 +331,6 @@ describe("DataFrame", function () {
             const df = new DataFrame(data, { columns: cols });
             assert.deepEqual(df.tail(2).values, [[20, 30, 40], [39, 89, 78]]);
         });
-        it("Throws error if row specified is greater than values", function () {
-            const data = [[1, 2, 3], [4, 5, 6], [20, 30, 40], [39, 89, 78]];
-            const cols = ["A", "B", "C"];
-            const df = new DataFrame(data, { columns: cols });
-            assert.throws(() => df.tail(10), Error,
-                "ParamError: Number of rows cannot be greater than available rows in data");
-        });
         it("Throws error if row specified is less than 0", function () {
             const data = [[1, 2, 3], [4, 5, 6], [20, 30, 40], [39, 89, 78]];
             const cols = ["A", "B", "C"];
@@ -357,6 +349,12 @@ describe("DataFrame", function () {
             const df = new DataFrame(data);
             assert.deepEqual(df.tail(2).values, [[1, 2, 34, 5, 0, 6, 4, 5, 6, 7], [20, 30, 40, 39, 89, 78, 45, 56, 56, 45]]);
         });
+        it("Returns all rows when size of DataFrame is less than default (5)", function () {
+            const data = [[1, 2, 3], [4, 5, 6], [20, 30, 40], [39, 89, 78]];
+            const cols = ["A", "B", "C"];
+            const df = new DataFrame(data, { columns: cols });
+            assert.deepEqual(df.tail().values, data);
+        });
     });
 
     describe("sample", function () {

diff --git a/src/danfojs-node/test/core/generic.test.ts b/src/danfojs-node/test/core/generic.test.ts
@@ -77,6 +77,19 @@ describe("Generic (NDFrame)", function () {
                     "IndexError: Row index must contain unique values"
             });
         });
+
+        it("Successfully create a 2D Frame when first value is empty", function () {
+            let data = [[null, 20, 1], [20, 25, 3]];
+            let ndframe = new NDframe({ data, isSeries: false });
+            //@ts-ignore
+            assert.deepEqual(ndframe.values, data);
+        });
+        it("Successfully create a 1D Frame when first value is empty", function () {
+            let data = [null, 'bval2', 'bval3', 'bval4'];
+            let ndframe = new NDframe({ data, isSeries: true });
+            //@ts-ignore
+            assert.deepEqual(ndframe.values, data);
+        });
     })
 
     describe("NDframe Created from JavaScript Object", function () {
@@ -123,70 +136,6 @@ describe("Generic (NDFrame)", function () {
             let ndframe = new NDframe({ data, isSeries: false });
             assert.deepEqual(ndframe.values as any, [["A", NaN], [NaN, 2]]);
         });
-        // it("NDframe created from json takes key position into consideration", function () {
-        //     let json_data = [{ A: "A", B: "B", C: "C" },
-        //     { A: "A", B: "B", C: "C" },
-        //     { C: "C", B: "B", A: "A" },
-        //     { A: "A", C: "C", B: "B" }];
-
-        //     let output = [
-        //         [
-        //             'A',
-        //             'B',
-        //             'C'
-        //         ],
-        //         [
-        //             'A',
-        //             'B',
-        //             'C'
-        //         ],
-        //         [
-        //             'A',
-        //             'B',
-        //             'C'
-        //         ],
-        //         [
-        //             'A',
-        //             'B',
-        //             'C'
-        //         ]
-        //     ];
-        //     let ndframe = new NDframe({ data: json_data, isSeries: false });
-        //     assert.deepEqual(ndframe.values, output);
-        // });
-
-        // it("NDframe created from json sets value to NaN if not present", function () {
-        //     let json_data = [{ A: "A", B: "B", C: "C" },
-        //     { A: "A", B: "B", C: "C" },
-        //     { C: "C", B: "B", A: "A" },
-        //     { A: "A", C: "C" }];
-
-        //     let output = [
-        //         [
-        //             'A',
-        //             'B',
-        //             'C'
-        //         ],
-        //         [
-        //             'A',
-        //             'B',
-        //             'C'
-        //         ],
-        //         [
-        //             'A',
-        //             'B',
-        //             'C'
-        //         ],
-        //         [
-        //             'A',
-        //             'B',
-        //             NaN
-        //         ]
-        //     ];
-        //     let ndframe = new NDframe({ data: json_data, isSeries: false });
-        //     assert.deepEqual(ndframe.values, output);
-        // });
-
     });
 
     describe("Replacing row data", function () {