12.3.10.4.3. Categoricals

import pandas as pd


dataFrame = pd.DataFrame({"id": [1, 2, 3, 4, 5, 6], "raw_grade": ["a", "b", "b", "a", "a", "e"]})

dataFrame["grade"] = dataFrame["raw_grade"].astype("category")

dataFrame["grade"].cat.categories = ["very good", "good", "very bad"]
dataFrame["grade"] = dataFrame["grade"].cat.set_categories(["very bad", "bad", "medium", "good", "very good"])
dataFrame["grade"]

0    very good
1         good
2         good
3    very good
4    very good
5     very bad
Name: grade, dtype: category
Categories (5, object): ['very bad', 'bad', 'medium', 'good', 'very good']

dataFrame.sort_values(by="grade")

	id	raw_grade	grade
5	6	e	very bad
1	2	b	good
2	3	b	good
0	1	a	very good
3	4	a	very good
4	5	a	very good

dataFrame.groupby("grade").size()

grade
very bad     1
bad          0
medium       0
good         2
very good    3
dtype: int64