Updated median with only numeric values

ml2/3_3_Data_Munging_with_Pandas.ipynb

@@ -404,7 +404,7 @@
    "outputs": [],
    "source": [
     "#Mean Age and SibSp of passengers grouped by passenger class and sex\n",
-    "df.groupby(['Pclass', 'Sex'])['Age','SibSp'].mean()"
+    "df.groupby(['Pclass', 'Sex'])[['Age','SibSp']].mean()"
    ]
   },
   {
@@ -414,7 +414,7 @@
    "outputs": [],
    "source": [
     "#Show mean  Age and  SibSp for passengers  older than 25 grouped by Passenger Class and Sex\n",
-    "df[df.Age > 25].groupby(['Pclass', 'Sex'])['Age','SibSp'].mean()"
+    "df[df.Age > 25].groupby(['Pclass', 'Sex'])[['Age','SibSp']].mean()"
    ]
   },
   {
@@ -424,7 +424,7 @@
    "outputs": [],
    "source": [
     "# Mean age, SibSp , Survived of passengers older than 25 which survived, grouped by Passenger Class and Sex \n",
-    "df[(df.Age > 25 & (df.Survived == 1))].groupby(['Pclass', 'Sex'])['Age','SibSp','Survived'].mean()"
+    "df[(df.Age > 25 & (df.Survived == 1))].groupby(['Pclass', 'Sex'])[['Age','SibSp','Survived']].mean()"
    ]
   },
   {
@@ -436,7 +436,7 @@
     "# We can also decide which function apply in each column\n",
     "\n",
     "#Show mean Age, mean SibSp, and number of passengers older than 25 that survived,  grouped by Passenger Class and Sex\n",
-    "df[(df.Age > 25 & (df.Survived == 1))].groupby(['Pclass', 'Sex'])['Age','SibSp','Survived'].agg({'Age': np.mean, \n",
+    "df[(df.Age > 25 & (df.Survived == 1))].groupby(['Pclass', 'Sex'])[['Age','SibSp','Survived']].agg({'Age': np.mean, \n",
     "                                                                         'SibSp': np.mean, 'Survived': np.sum})"
    ]
   },
@@ -600,8 +600,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# Fill missing values with the median\n",
-    "df_filled = df.fillna(df.median())\n",
+    "# Fill missing values with the median, we avoid empty (None) values with numeric_only\n",
+    "df_filled = df.fillna(df.median(numeric_only=True))\n",
     "df_filled[-5:]"
    ]
   },
@@ -685,7 +685,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# But we are working on a copy \n",
+    "# But we are working on a copy, so we get a warning\n",
     "df.iloc[889]['Sex'] = np.nan"
    ]
   },
@@ -695,7 +695,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# If we want to change, we should not chain selections\n",
+    "# If we want to change it, we should not chain selections\n",
     "# The selection can be done with the column name\n",
     "df.loc[889, 'Sex']"
    ]
@@ -932,11 +932,11 @@
    "metadata": {},
    "source": [
     "* [Pandas](http://pandas.pydata.org/)\n",
-    "* [Learning Pandas, Michael Heydt, Packt Publishing, 2015](http://proquest.safaribooksonline.com/book/programming/python/9781783985128)\n",
-    "* [Useful Pandas Snippets](https://gist.github.com/bsweger/e5817488d161f37dcbd2)\n",
-    "* [Pandas. Introduction to Data Structures](http://pandas.pydata.org/pandas-docs/stable/dsintro.html#dsintro)\n",
+    "* [Learning Pandas, Michael Heydt, Packt Publishing, 2017](https://learning.oreilly.com/library/view/learning-pandas/9781787123137/)\n",
+    "* [Pandas. Introduction to Data Structures](https://pandas.pydata.org/pandas-docs/stable/user_guide/dsintro.html)\n",
     "* [Introducing Pandas Objects](https://www.oreilly.com/learning/introducing-pandas-objects)\n",
-    "* [Boolean Operators in Pandas](http://pandas.pydata.org/pandas-docs/stable/indexing.html#boolean-operators)"
+    "* [Boolean Operators in Pandas](https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#boolean-operators)\n",
+    "* [Useful Pandas Snippets](https://gist.github.com/bsweger/e5817488d161f37dcbd2)"
    ]
   },
   {
@@ -958,7 +958,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },
@@ -972,7 +972,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.1"
+   "version": "3.8.12"
   },
   "latex_envs": {
    "LaTeX_envs_menu_present": true,