2885. Rename Columns

1import java.util.Map;
2import java.util.HashMap;
3import org.apache.commons.collections4.map.HashedMap; // Apache Commons Collections library for the map
4
5public class DataFrameUtils {
6
7    /**
8     * This method renames specific columns of a DataFrame to standardized names.
9     *
10     * @param studentsDf A DataFrame object containing student information with columns to be renamed.
11     * @return A DataFrame with renamed columns.
12     */
13    public static DataFrame renameColumns(DataFrame studentsDf) {
14        // Define a mapping from old column names to new standardized column names
15        Map<String, String> columnRenameMapping = new HashMap<>();
16        columnRenameMapping.put("id", "student_id");
17        columnRenameMapping.put("first", "first_name");
18        columnRenameMapping.put("last", "last_name");
19        columnRenameMapping.put("age", "age_in_years");
20      
21        // Create a new DataFrame for the renamed columns
22        DataFrame studentsDfRenamed = new DataFrame();
23      
24        // Iterate over each column, renaming as necessary
25        for (String column : studentsDf.getColumns()) {
26            if (columnRenameMapping.containsKey(column)) {
27                // If the column is in the mapping, rename it
28                studentsDfRenamed.renameColumn(column, columnRenameMapping.get(column));
29            } else {
30                // Otherwise, keep the original name
31                studentsDfRenamed.renameColumn(column, column);
32            }
33        }
34      
35        return studentsDfRenamed;
36    }
37
38    // DataFrame here is assumed to be a custom class similar to the pandas DataFrame.
39    // This custom class should have methods for getting column names and renaming columns.
40
41    // The renameColumns method can be used as follows:
42    // Assume studentsDf is a DataFrame with columns 'id', 'first', 'last', and 'age'
43    // DataFrame renamedStudentsDf = DataFrameUtils.renameColumns(studentsDf);
44}
45

1#include <string>
2#include <unordered_map>
3#include <iostream>
4// Include header for DataFrame if using a third-party library
5
6class DataFrame {
7    // This is a placeholder for the actual DataFrame implementation.
8    // It should provide capabilities similar to pandas.DataFrame in Python.
9public:
10    void rename_columns(const std::unordered_map<std::string, std::string>& column_rename_mapping) {
11        // Implementation of column renaming would go here.
12        // This is a stub to illustrate how it might work.
13    }
14};
15
16DataFrame rename_columns(DataFrame& students_df) {
17    // This function renames specific columns of a DataFrame to standardized names.
18    // It takes a DataFrame by reference and returns a new DataFrame with the columns renamed.
19  
20    // Define a mapping from old column names to new standardized column names
21    std::unordered_map<std::string, std::string> column_rename_mapping = {
22        {"id", "student_id"},
23        {"first", "first_name"},
24        {"last", "last_name"},
25        {"age", "age_in_years"}
26    };
27  
28    // Create a new DataFrame for the results
29    DataFrame students_df_renamed = students_df; // This assumes we have a copy constructor
30
31    // Rename the columns using the provided mapping
32    students_df_renamed.rename_columns(column_rename_mapping);
33  
34    return students_df_renamed;
35}
36
37// Usage example
38/*
39DataFrame students_df; // Assume students_df is initialized and populated with student data and the appropriate columns
40DataFrame renamed_students_df = rename_columns(students_df);
41*/
42

1// Import statement would not be needed in TypeScript as we're not using a direct equivalent of pandas.
2
3// Define an interface for the student object to specify the structure and types of the input data.
4interface Student {
5  id: number;
6  first: string;
7  last: string;
8  age: number;
9}
10
11// Define an interface for the student object with standardized names.
12interface RenamedStudent {
13  student_id: number;
14  first_name: string;
15  last_name: string;
16  age_in_years: number;
17}
18
19function renameColumns(students: Student[]): RenamedStudent[] {
20  /**
21   * This function renames specific properties of objects within an array to standardized names.
22   * 
23   * @param students An array of Student objects containing student information with properties to be renamed.
24   * @returns An array of RenamedStudent objects with renamed properties.
25   */
26  // Create a new array to hold the renamed student objects.
27  const renamedStudents: RenamedStudent[] = students.map(student => {
28    // Create a new object with the standardized property names.
29    const renamedStudent: RenamedStudent = {
30      student_id: student.id,
31      first_name: student.first,
32      last_name: student.last,
33      age_in_years: student.age
34    };
35    return renamedStudent;
36  });
37
38  // Return the new array with the renamed objects.
39  return renamedStudents;
40}
41
42// Example usage:
43// Assume students is an array of Student objects with properties 'id', 'first', 'last', and 'age'
44// const renamedStudents = renameColumns(students);
45