1907. Count Salary Categories

Table: Accounts

+-------------+------+
| Column Name | Type |
+-------------+------+
| account_id  | int  |
| income      | int  |
+-------------+------+
account_id is the primary key (column with unique values) for this table.
Each row contains information about the monthly income for one bank account.
 

Write a solution to calculate the number of bank accounts for each salary category. The salary categories are:

"Low Salary": All the salaries strictly less than $20000.
"Average Salary": All the salaries in the inclusive range [$20000, $50000].
"High Salary": All the salaries strictly greater than $50000.
The result table must contain all three categories. If there are no accounts in a category, return 0.

Return the result table in any order.

import pandas as pd

def count_salary_categories(accounts: pd.DataFrame) -> pd.DataFrame:
    bins = [-float('inf'), 19999, 50000, float('inf')]
    labels = ['Low Salary', 'Average Salary', 'High Salary']
    accounts['category'] = pd.cut(accounts['income'], bins=bins, labels=labels)
    return accounts['category'].value_counts().reset_index().rename(columns={'count': 'accounts_count'}).sort_values(by='accounts_count', ascending=False)