02. Excel Functions

import java.util.*;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int line = Integer.parseInt(scanner.nextLine());
        List<String> header = Arrays.stream(scanner.nextLine().split(", +"))
                .collect(Collectors.toCollection(ArrayList::new));

        List<List<String>> table = new ArrayList<>();


        for (int row = 0; row < line - 1; row++) {
            List<String> input = Arrays.stream(scanner.nextLine().split(", +"))
                    .collect(Collectors.toCollection(ArrayList::new));
            table.add(input);
        }

        String[] command = scanner.nextLine().split("\\s+");
        int colIndex = header.indexOf(command[1]);

        List<List<String>> result = new ArrayList<>();

        switch (command[0]) {
            case "sort":
                result = table.stream()
                        .sorted(Comparator.comparing(a -> a.get(colIndex))).collect(Collectors.toList());
                break;
            case "hide":
                table.forEach(e -> e.remove(colIndex));
                header.remove(colIndex);
                result = table;
                break;
            case "filter":
                String toFilter = command[2];
                result = table.stream().filter(e -> e.get(colIndex).equals(toFilter)).collect(Collectors.toList());
                break;
        }
        System.out.println(String.join(" | ", header));
        result.forEach(e -> System.out.println(String.join(" | ", e)));
    }
}