Problem

DataFrame students
+-------------+--------+
| Column Name | Type   |
+-------------+--------+
| id          | int    |
| first       | object |
| last        | object |
| age         | int    |
+-------------+--------+

Write a solution to rename the columns as follows:

  • id to student_id
  • first to first_name
  • last to last_name
  • age to age_in_years

The result format is in the following example.

### Examples

Example 1

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    Input: +----+---------+----------+-----+
    | id | first   | last     | age |
    +----+---------+----------+-----+
    | 1  | Mason   | King     | 6   |
    | 2  | Ava     | Wright   | 7   |
    | 3  | Taylor  | Hall     | 16  |
    | 4  | Georgia | Thompson | 18  |
    | 5  | Thomas  | Moore    | 10  |
    +----+---------+----------+-----+
    Output:
    +------------+------------+-----------+--------------+
    | student_id | first_name | last_name | age_in_years |
    +------------+------------+-----------+--------------+
    | 1          | Mason      | King      | 6            |
    | 2          | Ava        | Wright    | 7            |
    | 3          | Taylor     | Hall      | 16           |
    | 4          | Georgia    | Thompson  | 18           |
    | 5          | Thomas     | Moore     | 10           |
    +------------+------------+-----------+--------------+
    Explanation: 
    The column names are changed accordingly.

## Solution

### Method 1 -
### Method 1 - DataFrame.rename()

#### Intuition
We need to rename columns in a pandas DataFrame. The `rename` method allows us to map old column names to new ones easily.

#### Approach
Use the `rename` method with a dictionary mapping old names to new names, and set `axis=1` or `columns=`.

#### Code
##### Python (pandas)
```python
# students is a pandas DataFrame
students = students.rename(columns={
    'id': 'student_id',
    'first': 'first_name',
    'last': 'last_name',
    'age': 'age_in_years'
})

Complexity

  • ⏰ Time complexity: O(N), where N is the number of columns (constant here).
  • 🧺 Space complexity: O(1), as the operation is in-place or returns a new DataFrame with the same data.