将第二组列名添加到数据框中

Question

我有以下数据框（df1）：

        C12      C34
     C1   C2   C3  C4
R1   11   21   31  a1
R2   de   bc   cc  b
R3   dc   ec   dc  c
R4   gc   gc   gc  d

我可以将每个2个名称的列名添加到一起并获取以下数据框（df2）：

       C12     
     C1   C2  
R1   11   21   
R2   de   bc   
R3   dc   ec   
R4   gc   gc

应添加C12和C34，以便我可以获得df2（C12）的子集：

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;


public class Genealogical {

private static List<Person> persons = new ArrayList<Person>();

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


    while(true)
    {
        String firstLine = input.nextLine();
        String[] splitted = firstLine.split(" : ");
        if(splitted.length == 0)
        {
            System.exit(0);
        }

        if(firstLine.contains("BIRTH"))
        {
            String childName = splitted[0].substring(6);
            birth(childName, splitted[1], splitted[2], splitted[3]);
        }

        else if(firstLine.contains("DEATH"))
        {
            if(!firstLine.contains(" : "))
            {
                if(persons.size() > 0)
                    persons.get(persons.size() - 1).kill(firstLine.substring(6));
            }
            else
            {
                String name = splitted[0].substring(6);
                getPerson(name).kill(splitted[1]);
            }
        }

        else if(firstLine.contains("ANCESTORS"))
        {
            String name = splitted[0].substring(10);

            Person ancestor = getPerson(name);
            for(Person p : persons)
            {
                if(p.getName().equals(name) || p.used)
                {
                    continue;
                }

                else
                {
                    p.used = true;
                    ancestor.addAncestors(p);
                }
            }
        }

        else if(firstLine.contains("DESCENDANTS"))
        {

            String name = splitted[0].substring(12);

            Person descendant = getPerson(name);
            for(Person p : persons)
            {
                if(p.getName().equals(name) || p.used)
                {
                    continue;
                }

                else
                {
                    p.used = true;
                    descendant.addDescendants(p);
                }
            }
        }

        else if(firstLine.contains("QUIT"))
        {
            if(persons.size() > 0)
            {
                for(int i = persons.size() - 1; i >= 0; i--)
                {
                    Person p = persons.get(i);

                    if(p.getAncestors().size() > 0)
                    {
                        printAncestor(p);

                    }

                    if(p.getDescendants().size() > 0)
                    {
                        printDescendant(p);
                    }

                }
            }

            System.exit(0);


        }
    }



}

public static void printAncestor(Person p)
{
    System.out.println("ANCESTORS of " + p.getName());
    for(Person ancestor : p.getAncestors())
    {
        System.out.println("  " + ancestor.getName() + " " + ancestor.getDate() + " -" + ancestor.getDeathdate());
        System.out.println("    " + ancestor.getDad().getName());
        System.out.println("    " + ancestor.getMom().getName());
    }

    System.out.println();
}

public static void printDescendant(Person p)
{
    System.out.println("DESCENDANTS of " + p.getName());
    for(Person descendant : p.getDescendants())
    {
        System.out.println("  " + descendant.getName() + " " + descendant.getDate() + " -" + descendant.getDeathdate());

    }

}

private static void birth(String child, String date, String mother, String father)
{

    Person mom = getPerson(mother);
    if(mom == null)
    {
        mom = new Person(null, null);
        mom.setName(mother);
    }
    Person dad = getPerson(father);
    if(dad == null)
    {
        dad = new Person(null, null);
        dad.setName(father);
    }

    Person childd = new Person(mom, dad);
    childd.setName(child);
    childd.setDate(date);

    persons.add(childd);

}

private static Person getPerson(String person)
{
    for(Person p : persons)
    {
        if(p.getName().equals(person))
        {
            return p;
        }

    }

    return null;
}

}

Answer 1

我不知道如何将第二组列名添加到数据框中。话虽如此，您可以通过创建包含所需列名称的向量来轻松实现此功能：

C12 <- c("C1", "C2")
C34 <- c("C3", "C4")
df1[C12]
#    C1 C2
# R1 11 21
# R2 de bc
# R3 dc ec
# R4 gc gc
df1[C34]
#    C3 C4
# R1 31 a1
# R2 cc  b
# R3 dc  c
# R4 gc  d

如果您想要按行进行子集化，则可以使用行名称：

R12 <- c("R1", "R2")
R34 <- c("R3", "R4")
df1[R12,]
#    C1 C2 C3 C4
# R1 11 21 31 a1
# R2 de bc cc  b
df1[R34,]
#    C1 C2 C3 C4
# R3 dc ec dc  c
# R4 gc gc gc  d