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This approach focuses on manipulating the data structures that hold the DataFrame or its equivalent to rename the columns. The idea is to access the data structure directly and modify the column headers.
Time Complexity: O(1) as renaming columns in a DataFrame does not depend on the number of rows.
Space Complexity: O(1), no additional space required beyond the rename operation.
1import pandas as pd
2
3def rename_columns
In Python, the Pandas library provides a rename function which can easily rename columns. The rename method takes a dictionary where keys are existing column names and values are the new names.
This approach relies on using specific libraries available for each programming language that are geared towards data manipulation. These libraries often offer built-in functionalities for renaming columns effortlessly.
Time Complexity: O(1) since column renaming is independent of the data in the table.
Space Complexity: O(1) because it modifies column names in-place.
1using System;
2using System.Collections.Generic;
3using System.Data;
4
5class Program {
6 static void Main() {
7 DataTable students = new DataTable();
8 students.Columns.Add("id", typeof(int));
9 students.Columns.Add("first", typeof(string));
10 students.Columns.Add("last", typeof(string));
11 students.Columns.Add("age", typeof(int));
12
13 students.Rows.Add(1, "Mason", "King", 6);
14 students.Rows.Add(2, "Ava", "Wright", 7);
15 students.Rows.Add(3, "Taylor", "Hall", 16);
16 students.Rows.Add(4, "Georgia", "Thompson", 18);
17 students.Rows.Add(5, "Thomas", "Moore", 10);
18
19 RenameColumns(students);
20
21 foreach (DataRow row in students.Rows) {
22 Console.WriteLine(string.Join(", ", row.ItemArray));
23 }
24 }
25
26 static void RenameColumns(DataTable table) {
27 table.Columns["id"].ColumnName = "student_id";
28 table.Columns["first"].ColumnName = "first_name";
29 table.Columns["last"].ColumnName = "last_name";
30 table.Columns["age"].ColumnName = "age_in_years";
31 }
32}In C#, the DataTable structure from System.Data namespace is used to represent the data. To rename columns, we update the ColumnName property of the appropriate columns in the DataTable.Columns collection.