LeetCode 题解工作台
修改列
DataFrame employees +-------------+--------+ | Column Name | Type | +-------------+--------+ | name | object | | salary | int | +-------------+-------…
0
题型
1
代码语言
0
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当前训练重点
简单 · Modify Columns core interview pattern
答案摘要
import pandas as pd def modifySalaryColumn(employees: pd.DataFrame) -> pd.DataFrame:
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题目描述
DataFrame employees
+-------------+--------+
| Column Name | Type |
+-------------+--------+
| name | object |
| salary | int |
+-------------+--------+
一家公司决定增加员工的薪水。
编写一个解决方案，将每个员工的薪水乘以2来 修改 salary 列。
返回结果格式如下示例所示。
示例 1:
输入： DataFrame employees +---------+--------+ | name | salary | +---------+--------+ | Jack | 19666 | | Piper | 74754 | | Mia | 62509 | | Ulysses | 54866 | +---------+--------+ 输出： +---------+--------+ | name | salary | +---------+--------+ | Jack | 39332 | | Piper | 149508 | | Mia | 125018 | | Ulysses | 109732 | +---------+--------+ 解释： 每个人的薪水都被加倍。
解题思路
方法一
import pandas as pd
def modifySalaryColumn(employees: pd.DataFrame) -> pd.DataFrame:
employees['salary'] *= 2
return employees
复杂度分析
| 指标 | 值 |
|---|---|
| 时间 | complexity is O(n) where n is the number of rows, due to column-wise operations. Space complexity is O(1) extra space if done in place, otherwise O(n) for creating a new column copy. |
| 空间 | Depends on the final approach |
面试官常问的追问
外企场景- question_mark
Emphasize vectorized column operations.
- question_mark
Check if the candidate avoids unnecessary loops.
- question_mark
Look for correct preservation of DataFrame structure.
常见陷阱
外企场景- error
Using explicit for-loops over rows, which is slower.
- error
Accidentally modifying other columns or changing row order.
- error
Forgetting to return or assign the updated DataFrame.
进阶变体
外企场景- arrow_right_alt
Multiply by a different constant or apply another arithmetic operation.
- arrow_right_alt
Modify multiple numeric columns at once using the same pattern.
- arrow_right_alt
Apply a conditional update only to certain rows based on a filter.