count group by pandas code example

Example 1: pandas groupby count as new column

In [12]: df.groupby(["item", "color"])["id"].count().reset_index(name="count")
Out[12]:
    item  color  count
0    car  black      2
1  truck   blue      1
2  truck    red      2

Example 2: group by count dataframe

df.groupby(['col1', 'col2']).size().reset_index(name='counts')

Example 3: group by count dataframe

df.groupby(['col1','col2']).size()

Example 4: pandas count values by column

df = pd.DataFrame({'a':list('abssbab')})
df.groupby('a').count()

Example 5: group by pandas count

df[['col1', 'col2', 'col3', 'col4']].groupby(['col1', 'col2']).agg(['mean', 'count'])