112. Count Salary Categories

[문제]

https://leetcode.com/problems/count-salary-categories/description/

 

[풀이]

1. category의 모든 범주를 가져와야 하므로 참조테이블을 만든다.

2. 각 범주에 해당하는 조건으로 행을 필터링하고 행의 개수를 세어준다.

3. 아래 코드는 1, 2 번을 동시에 하는 방법이다

 

Pandas

import pandas as pd

def count_salary_categories(accounts: pd.DataFrame) -> pd.DataFrame:

    return pd.DataFrame({
        'category': ['Low Salary', 'Average Salary', 'High Salary'],
        'accounts_count': [
            accounts[accounts.income < 20000].shape[0],
            accounts[(accounts.income >= 20000) & (accounts.income <= 50000)].shape[0],
            accounts[accounts.income > 50000].shape[0]
        ]
    })

 

SQL

SELECT 
    'Low Salary' AS category
    , (SELECT COUNT(*) FROM Accounts WHERE income < 20000) AS accounts_count
UNION ALL
SELECT 
    'Average Salary'
    , (SELECT COUNT(*) FROM Accounts WHERE income >= 20000 AND income <= 50000)
UNION ALL
SELECT 
    'High Salary'
    , (SELECT COUNT(*) FROM Accounts WHERE income > 50000)

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