Problem
Table: Users
+----------------+---------+
| Column Name | Type |
+----------------+---------+
| user_id | int |
| name | varchar |
+----------------+---------+
user_id
is the primary key (column with unique values) for this table.
This table contains the ID and the name of the user. The name consists of only lowercase and uppercase characters.
Write a solution to fix the names so that only the first character is uppercase and the rest are lowercase.
Return the result table ordered by user_id
.
The result format is in the following example.
Examples
Example 1:
Input: Users table:
+---------+-------+
| user_id | name |
+---------+-------+
| 1 | aLice |
| 2 | bOB |
+---------+-------+
Output:
+---------+-------+
| user_id | name |
+---------+-------+
| 1 | Alice |
| 2 | Bob |
+---------+-------+
Solution
Method 1 - Using Substring
Code
SQL
SELECT Users.user_id , CONCAT(UPPER(SUBSTR(Users.name,1,1)),LOWER(SUBSTR(Users.name,2))) AS name
FROM Users
ORDER BY
Users.user_id ASC
Pandas
- Apply the
str.capitalize()
function to fix the names - Sort the result table by
user_id
in ascending order
import pandas as pd
def fix_names(users: pd.DataFrame) -> pd.DataFrame:
users['name'] = users['name'].str.capitalize()
result_df = users.sort_values(by='user_id', ascending=True)
return result_df
Complexity
- Time:
O(n)
- Space:
O(1)