Classification/gradient_boosted_decision_trees.ipynb

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   "cell_type": "markdown",
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   "source": [
    "# Supervised Learning Algorithms: Gradient-boosted Decision Trees"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "*In this template, only **data input** and **input/target variables** need to be specified (see \"Data Input & Variables\" section for further instructions). None of the other sections needs to be adjusted. As a data input example, .csv file from IBM Box web repository is used.*"
   ]
  },
  {
   "cell_type": "markdown",
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   "source": [
    "## 1. Libraries"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "*Run to import the required libraries.*"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "%matplotlib notebook\n",
    "import numpy as np\n",
    "import pandas as pd\n",
    "from sklearn.model_selection import train_test_split"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 2. Data Input and Variables"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "*Define the data input as well as the input (X) and target (y) variables and run the code. Do not change the data & variable names **['df', 'X', 'y']** as they are used in further sections.*"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "### Data Input\n",
    "# df = \n",
    "\n",
    "### Defining Variables  \n",
    "# X = \n",
    "# y = \n",
    "\n",
    "### Data Input Example \n",
    "df = pd.read_csv('https://ibm.box.com/shared/static/q6iiqb1pd7wo8r3q28jvgsrprzezjqk3.csv')\n",
    "\n",
    "X = df[['horsepower', 'normalized-losses']]\n",
    "y = df['price']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 3. The Model"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "*Run to build the model.*"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Car dataset (learning_rate=0.1, max_depth=3)\n",
      "Accuracy of GBDT classifier on training set: 0.64\n",
      "Accuracy of GBDT classifier on test set: 0.02\n",
      "\n",
      "Car dataset (learning_rate=0.01, max_depth=2)\n",
      "Accuracy of GBDT classifier on training set: 0.67\n",
      "Accuracy of GBDT classifier on test set: 0.02\n"
     ]
    }
   ],
   "source": [
    "from sklearn.ensemble import GradientBoostingClassifier\n",
    "\n",
    "X_train, X_test, y_train, y_test = train_test_split(X, y, random_state = 0)\n",
    "\n",
    "#### COMPARE YOUR MODELS ####\n",
    "\n",
    "# Model with the learning rate = 0.1 and max_dept = 3 (default settings)\n",
    "clf = GradientBoostingClassifier(random_state = 0).fit(X_train, y_train)\n",
    "\n",
    "print('Car dataset (learning_rate=0.1, max_depth=3)')\n",
    "print('Accuracy of GBDT classifier on training set: {:.2f}'\n",
    "     .format(clf.score(X_train, y_train)))\n",
    "print('Accuracy of GBDT classifier on test set: {:.2f}\\n'\n",
    "     .format(clf.score(X_test, y_test)))\n",
    "\n",
    "# Model with the learning rate = 0.01 and max_dept = 2\n",
    "clf = GradientBoostingClassifier(learning_rate = 0.01, max_depth = 2, random_state = 0).fit(X_train, y_train)\n",
    "\n",
    "print('Car dataset (learning_rate=0.01, max_depth=2)')\n",
    "print('Accuracy of GBDT classifier on training set: {:.2f}'\n",
    "     .format(clf.score(X_train, y_train)))\n",
    "print('Accuracy of GBDT classifier on test set: {:.2f}'\n",
    "     .format(clf.score(X_test, y_test)))"
   ]
  }
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