Swap Sex of Employees — LeetCode 627 Python Solution

The problem

Flip the sex column of every row in place, turning every m into an f and every f into an m, with a single update statement and no temporary table. The answer is the Salary table itself once the update has run. The Salary table has one row per employee: id (int, the primary key), name (varchar), sex (an enum whose only values are 'm' and 'f') and salary (int).

Example

Salary table:

| id | name  | sex | salary |
| -- | ----- | --- | ------ |
| 1  | Lena  | f   | 5200   |
| 2  | Marco | m   | 4800   |
| 3  | Nia   | f   | 6100   |
| 4  | Omar  | m   | 4400   |

Salary table after the update:

| id | name  | sex | salary |
| -- | ----- | --- | ------ |
| 1  | Lena  | m   | 5200   |
| 2  | Marco | f   | 4800   |
| 3  | Nia   | m   | 6100   |
| 4  | Omar  | f   | 4400   |

Every value in the sex column is replaced by its opposite in one pass, and no other column moves.

Python solution

import pandas as pd

def swap_sex(salary: pd.DataFrame) -> pd.DataFrame:
    df = salary.copy()
    df['sex'] = df['sex'].map(lambda x: 'f' if x == 'm' else 'm')
    return df

Complexity

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