Learn Python by Building Data Science Applications

Descriptive statistics

Now, having a dataframe in place, let's answer some simple questions; for example, which battles took the most lives on both sides? To answer that, we need to add two columns, sort the dataframe by the result, from larger to smaller, and print out first N records. Let's do it:

>>> kill_cols = ['allies killed', 'axis killed']>>> data['killed total'] = data[kill_cols].sum(1)>>> data['killed total'].sort_values(ascending=False).head(3)>>> name
Battle of Stalingrad     1997993.0
Battle of Moscow         1203428.0
Battle of Kiev (1941)     661958.0
Name: killed total, dtype: float64

The next question might be on the typical number of casualties for each battle. Before we calculate the statistics, we have to filter rows with unknown (NaN) ...