Sort DataFrames by Multiple Columns in Mixed Directions in Pandas

Question

Given an `employee_df`, sort by `department` alphabetically ascending, and within each department sort by `salary` descending. Place employees with missing salaries at the end.

Accepted Answer

Optimal Solution:
import pandas as pd

sorted_df = employee_df.sort_values(
    by=['department', 'salary'],
    ascending=[True, False],
    na_position='last'
)

Technical Explanation:
Passing a list of booleans to `ascending=[True, False]` assigns independent sort directions to each column in `by`. `na_position='last'` keeps nulls at the end.

name	department	salary
Aarav	Analytics	85000
Bhavna	Analytics	95000
Chirag	Engineering	90000

name	department	salary
Bhavna	Analytics	95000
Aarav	Analytics	85000
Chirag	Engineering	90000