adding version to iris dataset (#539)

* adding version to iris dataset

* adding version to iris dataset

* adding test cases for iris dataset

* adding test cases for iris dataset

* some minor changes

Author: janismdhanbad

Diff for: docs/sources/CHANGELOG.md

@@ -16,8 +16,11 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
+- Added an enhancement to the existing `iris_data()` such that both the UCI Repository version of the Iris dataset as well as the corrected, original
+  version of the dataset can be loaded, which has a slight difference in two data points (consistent with Fisher's paper; this is also the same as in R). (via [#539](https://github.com/rasbt/mlxtend/pull/532) via [janismdhanbad](https://github.com/janismdhanbad))
 - Add optional `groups` parameter to `SequentialFeatureSelector` and `ExhaustiveFeatureSelector` `fit()` methods for forwarding to sklearn CV ([#537](https://github.com/rasbt/mlxtend/pull/537) via [arc12](https://github.com/qiaguhttps://github.com/arc12))
 
+
 ##### Changes
 
 - -

Diff for: docs/sources/user_guide/data/iris_data.ipynb

@@ -131,7 +131,7 @@
      "text": [
       "## iris_data\n",
       "\n",
-      "*iris_data()*\n",
+      "*iris_data(version='uci')*\n",
       "\n",
       "Iris flower dataset.\n",
       "\n",
@@ -153,6 +153,17 @@
       "    - 3) petal length [cm]\n",
       "    - 4) petal width [cm]\n",
       "\n",
+      "\n",
+      "**Parameters**\n",
+      "\n",
+      "- `version` : string, optional (default: 'uci').\n",
+      "\n",
+      "    Version to use {'uci', 'corrected'}. 'uci' loads the dataset\n",
+      "    as deposited on the UCI machine learning repository, and\n",
+      "    'corrected' provides the version that is consistent with\n",
+      "    Fisher's original paper. See Note for details.\n",
+      "\n",
+      "\n",
       "**Returns**\n",
       "\n",
       "- `X, y` : [n_samples, n_features], [n_class_labels]\n",
@@ -167,10 +178,12 @@
       "\n",
       "The Iris dataset (originally collected by Edgar Anderson) and\n",
       "    available in UCI's machine learning repository is different from\n",
-      "    the Iris dataset available in R(and the one in the original paper\n",
-      "    by R.A. Fisher [1]). Precisely, there are two data points(row number\n",
+      "    the Iris dataset described in the original paper by  R.A. Fisher [1]).\n",
+      "    Precisely, there are two data points (row number\n",
       "    34 and 37) in UCI's Machine Learning repository are different from the\n",
-      "    Iris dataset in R (and the one in the original Fisher paper).\n",
+      "    origianlly published Iris dataset. Also, the original version of the Iris\n",
+      "    Dataset, which can be loaded via `version='corrected'` is the same\n",
+      "    as the one in R.\n",
       "\n",
       "    [1] . A. Fisher (1936). \"The use of multiple measurements in taxonomic\n",
       "    problems\". Annals of Eugenics. 7 (2): 179–188\n",
@@ -193,9 +206,9 @@
  "metadata": {
   "anaconda-cloud": {},
   "kernelspec": {
-   "display_name": "mlxtend_dev",
+   "display_name": "Python 3",
    "language": "python",
-   "name": "mlxtend_dev"
+   "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
@@ -207,7 +220,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.8"
+   "version": "3.7.1"
   },
   "toc": {
    "nav_menu": {},
@@ -223,5 +236,5 @@
   }
  },
  "nbformat": 4,
- "nbformat_minor": 1
+ "nbformat_minor": 2
 }