diff --git a/pandas/pandas.ipynb b/pandas/pandas.ipynb
index 1198a7c..d0d722d 100644
--- a/pandas/pandas.ipynb
+++ b/pandas/pandas.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:56fea349850ffa0f72e6b8900647ed0f5ede765deae5932b1a26237f03166107"
+  "signature": "sha256:4c3e3bc5e2e66a53e95dce82d5f14b65d389cff01d434f1cf65ee91981716551"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -588,11 +588,11 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "data_1 = {'state': ['VA', 'VA', 'VA', 'MD', 'MD'],\n",
-      "        'year': [2012, 2013, 2014, 2014, 2015],\n",
-      "        'pop': [5.0, 5.1, 5.2, 4.0, 4.1]}\n",
-      "frame_1 = DataFrame(data_1)\n",
-      "frame_1"
+      "data_1 = {'state' : ['VA', 'VA', 'VA', 'MD', 'MD'],\n",
+      "          'year' : [2012, 2013, 2014, 2014, 2015],\n",
+      "          'pop' : [5.0, 5.1, 5.2, 4.0, 4.1]}\n",
+      "df_1 = DataFrame(data_1)\n",
+      "df_1"
      ],
      "language": "python",
      "metadata": {},
@@ -670,8 +670,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_2 = DataFrame(data_1, columns=['year', 'state', 'pop'])\n",
-      "frame_2"
+      "df_2 = DataFrame(data_1, columns=['year', 'state', 'pop'])\n",
+      "df_2"
      ],
      "language": "python",
      "metadata": {},
@@ -749,8 +749,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3 = DataFrame(data_1, columns=['year', 'state', 'pop', 'unempl'])\n",
-      "frame_3"
+      "df_3 = DataFrame(data_1, columns=['year', 'state', 'pop', 'unempl'])\n",
+      "df_3"
      ],
      "language": "python",
      "metadata": {},
@@ -834,7 +834,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3['state']"
+      "df_3['state']"
      ],
      "language": "python",
      "metadata": {},
@@ -866,7 +866,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3.year"
+      "df_3.year"
      ],
      "language": "python",
      "metadata": {},
@@ -898,7 +898,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3.ix[0]"
+      "df_3.ix[0]"
      ],
      "language": "python",
      "metadata": {},
@@ -929,8 +929,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3['unempl'] = np.arange(5)\n",
-      "frame_3"
+      "df_3['unempl'] = np.arange(5)\n",
+      "df_3"
      ],
      "language": "python",
      "metadata": {},
@@ -1015,8 +1015,8 @@
      "collapsed": false,
      "input": [
       "unempl = Series([6.0, 6.0, 6.1], index=[2, 3, 4])\n",
-      "frame_3['unempl'] = unempl\n",
-      "frame_3"
+      "df_3['unempl'] = unempl\n",
+      "df_3"
      ],
      "language": "python",
      "metadata": {},
@@ -1100,8 +1100,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3['state_dup'] = frame_3['state']\n",
-      "frame_3"
+      "df_3['state_dup'] = df_3['state']\n",
+      "df_3"
      ],
      "language": "python",
      "metadata": {},
@@ -1191,8 +1191,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "del frame_3['state_dup']\n",
-      "frame_3"
+      "del df_3['state_dup']\n",
+      "df_3"
      ],
      "language": "python",
      "metadata": {},
@@ -1278,8 +1278,8 @@
      "input": [
       "pop = {'VA' : {2013 : 5.1, 2014 : 5.2},\n",
       "       'MD' : {2014 : 4.0, 2015 : 4.1}}\n",
-      "frame_4 = DataFrame(pop)\n",
-      "frame_4"
+      "df_4 = DataFrame(pop)\n",
+      "df_4"
      ],
      "language": "python",
      "metadata": {},
@@ -1339,7 +1339,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_4.T"
+      "df_4.T"
      ],
      "language": "python",
      "metadata": {},
@@ -1396,10 +1396,10 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "data_2 = {'VA' : frame_4['VA'][1:],\n",
-      "          'MD' : frame_4['MD'][2:]}\n",
-      "frame_5 = DataFrame(data_2)\n",
-      "frame_5"
+      "data_2 = {'VA' : df_4['VA'][1:],\n",
+      "          'MD' : df_4['MD'][2:]}\n",
+      "df_5 = DataFrame(data_2)\n",
+      "df_5"
      ],
      "language": "python",
      "metadata": {},
@@ -1453,8 +1453,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_5.index.name = 'year'\n",
-      "frame_5"
+      "df_5.index.name = 'year'\n",
+      "df_5"
      ],
      "language": "python",
      "metadata": {},
@@ -1514,8 +1514,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_5.columns.name = 'state'\n",
-      "frame_5"
+      "df_5.columns.name = 'state'\n",
+      "df_5"
      ],
      "language": "python",
      "metadata": {},
@@ -1575,7 +1575,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_5.values"
+      "df_5.values"
      ],
      "language": "python",
      "metadata": {},
@@ -1603,7 +1603,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3.values"
+      "df_3.values"
      ],
      "language": "python",
      "metadata": {},
@@ -1641,7 +1641,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3"
+      "df_3"
      ],
      "language": "python",
      "metadata": {},
@@ -1725,7 +1725,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3.reindex(list(reversed(range(0, 6))))"
+      "df_3.reindex(list(reversed(range(0, 6))))"
      ],
      "language": "python",
      "metadata": {},
@@ -1817,7 +1817,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3.reindex(range(6, 0), fill_value=0)"
+      "df_3.reindex(range(6, 0), fill_value=0)"
      ],
      "language": "python",
      "metadata": {},
@@ -1931,7 +1931,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3.reindex(columns=['state', 'pop', 'unempl', 'year'])"
+      "df_3.reindex(columns=['state', 'pop', 'unempl', 'year'])"
      ],
      "language": "python",
      "metadata": {},
@@ -2015,9 +2015,9 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_3.reindex(index=list(reversed(range(0, 6))),\n",
-      "                fill_value=0,\n",
-      "                columns=['state', 'pop', 'unempl', 'year'])"
+      "df_3.reindex(index=list(reversed(range(0, 6))),\n",
+      "             fill_value=0,\n",
+      "             columns=['state', 'pop', 'unempl', 'year'])"
      ],
      "language": "python",
      "metadata": {},
@@ -2109,8 +2109,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6 = frame_3.ix[range(0, 7), ['state', 'pop', 'unempl', 'year']]\n",
-      "frame_6"
+      "df_6 = df_3.ix[range(0, 7), ['state', 'pop', 'unempl', 'year']]\n",
+      "df_6"
      ],
      "language": "python",
      "metadata": {},
@@ -2217,8 +2217,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_7 = frame_6.drop([0, 1])\n",
-      "frame_7"
+      "df_7 = df_6.drop([0, 1])\n",
+      "df_7"
      ],
      "language": "python",
      "metadata": {},
@@ -2302,8 +2302,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_7 = frame_7.drop('unempl', axis=1)\n",
-      "frame_7"
+      "df_7 = df_7.drop('unempl', axis=1)\n",
+      "df_7"
      ],
      "language": "python",
      "metadata": {},
@@ -2599,7 +2599,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6"
+      "df_6"
      ],
      "language": "python",
      "metadata": {},
@@ -2699,7 +2699,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6[['pop', 'unempl']]"
+      "df_6[['pop', 'unempl']]"
      ],
      "language": "python",
      "metadata": {},
@@ -2783,7 +2783,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6[:2]"
+      "df_6[:2]"
      ],
      "language": "python",
      "metadata": {},
@@ -2843,7 +2843,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6[frame_6['pop'] > 5]"
+      "df_6[df_6['pop'] > 5]"
      ],
      "language": "python",
      "metadata": {},
@@ -2903,7 +2903,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6 > 5"
+      "df_6 > 5"
      ],
      "language": "python",
      "metadata": {},
@@ -3003,7 +3003,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6[frame_6 > 5]"
+      "df_6[df_6 > 5]"
      ],
      "language": "python",
      "metadata": {},
@@ -3103,7 +3103,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6.ix[2:3]"
+      "df_6.ix[2:3]"
      ],
      "language": "python",
      "metadata": {},
@@ -3163,8 +3163,8 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6.ix[0:2, 'pop']\n",
-      "frame_6"
+      "df_6.ix[0:2, 'pop']\n",
+      "df_6"
      ],
      "language": "python",
      "metadata": {},
@@ -3264,7 +3264,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_6.ix[frame_6.unempl > 5.0]"
+      "df_6.ix[df_6.unempl > 5.0]"
      ],
      "language": "python",
      "metadata": {},
@@ -3457,9 +3457,9 @@
      "collapsed": false,
      "input": [
       "np.random.seed(0)\n",
-      "frame_8 = DataFrame(np.random.rand(9).reshape((3, 3)),\n",
-      "                    columns=['a', 'b', 'c'])\n",
-      "frame_8"
+      "df_8 = DataFrame(np.random.rand(9).reshape((3, 3)),\n",
+      "                 columns=['a', 'b', 'c'])\n",
+      "df_8"
      ],
      "language": "python",
      "metadata": {},
@@ -3517,9 +3517,9 @@
      "collapsed": false,
      "input": [
       "np.random.seed(1)\n",
-      "frame_9 = DataFrame(np.random.rand(9).reshape((3, 3)),\n",
-      "                    columns=['b', 'c', 'd'])\n",
-      "frame_9"
+      "df_9 = DataFrame(np.random.rand(9).reshape((3, 3)),\n",
+      "                 columns=['b', 'c', 'd'])\n",
+      "df_9"
      ],
      "language": "python",
      "metadata": {},
@@ -3583,7 +3583,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_8 + frame_9"
+      "df_8 + df_9"
      ],
      "language": "python",
      "metadata": {},
@@ -3651,7 +3651,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "frame_8.add(frame_9, fill_value=0)"
+      "df_8.add(df_9, fill_value=0)"
      ],
      "language": "python",
      "metadata": {},