LeetCode 题解工作台
数据选取
DataFrame students +-------------+--------+ | Column Name | Type | +-------------+--------+ | student_id | int | | name | object | | age | int | +----…
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题型
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代码语言
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简单 · Select Data core interview pattern
答案摘要
import pandas as pd def selectData(students: pd.DataFrame) -> pd.DataFrame:
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题目描述
DataFrame students +-------------+--------+ | Column Name | Type | +-------------+--------+ | student_id | int | | name | object | | age | int | +-------------+--------+
编写一个解决方案，选择 student_id = 101 的学生的 name 和 age 并输出。
返回结果格式如下示例所示。
示例 1:
输入： +------------+---------+-----+ | student_id | name | age | +------------+---------+-----+ | 101 | Ulysses | 13 | | 53 | William | 10 | | 128 | Henry | 6 | | 3 | Henry | 11 | +------------+---------+-----+ 输出： +---------+-----+ | name | age | +---------+-----+ | Ulysses | 13 | +---------+-----+ 解释： 学生 Ulysses 的 student_id = 101，所以我们输出了他的 name 和 age。
解题思路
方法一
import pandas as pd
def selectData(students: pd.DataFrame) -> pd.DataFrame:
return students[students['student_id'] == 101][['name', 'age']]
复杂度分析
| 指标 | 值 |
|---|---|
| 时间 | complexity depends on the method used; filtering a single row is generally O(n) in table size. Space complexity is minimal since only one row and two columns are selected. |
| 空间 | Depends on the final approach |
面试官常问的追问
外企场景- question_mark
Expect precise row filtering using the student_id column.
- question_mark
Check for column-specific selection to ensure only name and age are returned.
- question_mark
Notice if the candidate avoids unnecessary full-table selection or extra columns.
常见陷阱
外企场景- error
Selecting all columns instead of only name and age, returning more data than needed.
- error
Using incorrect conditions, e.g., filtering with the wrong student_id.
- error
Returning multiple rows when the query should only produce one row for student_id 101.
进阶变体
外企场景- arrow_right_alt
Select multiple students by providing a list of student_ids instead of a single ID.
- arrow_right_alt
Retrieve additional columns such as grade while still filtering by student_id.
- arrow_right_alt
Filter by conditions other than student_id, such as age greater than a certain value.