update groupby.apply to pass in array of series as DataFrame into apply callback function. inspired by #221

Author: steveoni

danfojs-node/src/core/groupby.js

@@ -1,6 +1,7 @@
 import { DataFrame } from "./frame";
 import { Utils } from "./utils";
 import { Series } from "./series";
+import { concat } from "./concat";
 const utils = new Utils;
 
 /**
@@ -267,9 +268,15 @@ export class GroupBy {
     function concatPathAndNode(path, node, col_dtype) {
       if (Array.isArray(node)) {
         if (Array.isArray(node[0])) {
-          const transposed_node = node[0].map((_, colIndex) => node.map((row) => row[colIndex]));
-          for (const n_array of transposed_node)
-            df_data.push(path.concat(n_array));
+          if (ops != "apply" ) {
+            const transposed_node = node[0].map((_, colIndex) => node.map((row) => row[colIndex]));
+            for (const n_array of transposed_node)
+              df_data.push(path.concat(n_array));
+          } else {
+            for (const n_array of node)
+              df_data.push(path.concat(n_array));
+          }
+
         } else
           df_data.push(path.concat(node));
       } else {
@@ -310,13 +317,20 @@ export class GroupBy {
     function recursiveCount(sub_df_data, sub_count_group) {
       for (const [ key, value ] of Object.entries(sub_df_data)) {
         if (Array.isArray(value)) {
-          sub_count_group[key] = value.map(( callable_value ) => {
-            const callable_rslt = callable(callable_value);
-            if ((callable_rslt instanceof DataFrame) || (callable_rslt instanceof Series))
-              return callable_rslt.values;
-            else
-              return callable_rslt;
-          });
+          let callable_value;
+          if (value.length > 1) {
+            callable_value = concat({ df_list: value, axis: 1 });
+          } else {
+            callable_value = value[0];
+          }
+          const callable_rslt = callable(callable_value);
+          if (callable_rslt instanceof DataFrame) {
+            column = callable_rslt.columns;
+            sub_count_group[key] = callable_rslt.values;
+          } else if (callable_rslt instanceof Series) {
+            sub_count_group[key] = callable_rslt.values;
+          } else
+            sub_count_group = callable_rslt;
         } else {
           sub_count_group[key] = {};
           recursiveCount(value, sub_count_group[key]);