problemeasyalgorithmsleetcode-2881leetcode 2881leetcode2881

Create a New Column

EasyUpdated: Aug 2, 2025
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Problem

DataFrame employees
+-------------+--------+
| Column Name | Type.  |
+-------------+--------+
| name        | object |
| salary      | int.   |
+-------------+--------+

A company plans to provide its employees with a bonus.

Write a solution to create a new column name bonus that contains the doubled values of the salary column.

The result format is in the following example.

Examples

Example 1


    
    
    Input:
    DataFrame employees
    +---------+--------+
    | name    | salary |
    +---------+--------+
    | Piper   | 4548   |
    | Grace   | 28150  |
    | Georgia | 1103   |
    | Willow  | 6593   |
    | Finn    | 74576  |
    | Thomas  | 24433  |
    +---------+--------+
    Output:
    +---------+--------+--------+
    | name    | salary | bonus  |
    +---------+--------+--------+
    | Piper   | 4548   | 9096   |
    | Grace   | 28150  | 56300  |
    | Georgia | 1103   | 2206   |
    | Willow  | 6593   | 13186  |
    | Finn    | 74576  | 149152 |
    | Thomas  | 24433  | 48866  |
    +---------+--------+--------+
    Explanation: 
    A new column bonus is created by doubling the value in the column salary.

## Solution

### Method 1 – Using pandas DataFrame Assignment

#### Intuition

The key idea is to use pandas' ability to assign a new column directly to a DataFrame. By multiplying the `salary` column by 2, we efficiently create the `bonus` column.

#### Approach

1. The function receives a DataFrame `employees` with columns `name` and `salary`.
2. Assign a new column `bonus` as `employees["salary"] * 2`.
3. Return the modified DataFrame.

#### Code

{{< code_tabs >}}
##### Python

```python
def createBonusColumn(employees: 'pd.DataFrame') -> 'pd.DataFrame':
    employees = employees.copy()
    employees["bonus"] = employees["salary"] * 2
    return employees

Complexity

  • ⏰ Time complexity: O(n), where n is the number of rows in employees, as each row is processed once.
  • 🧺 Space complexity: O(n), for storing the new DataFrame.

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