我编写了自己的java程序，实现了一个arraylist来存储2列，比如a和b，并将它们复制到2d矩阵中，形成标题和1列行，在a和b的匹配中使用c值。。。
让我知道如果有一个更好的方式代码下面
csvreader reader=null；

try {  reader = new CSVReader(new FileReader(args[0]));
                } catch (FileNotFoundException e) { e.printStackTrace();
                }

     String [] field_name;
     ArrayList<String> listRows = new ArrayList<String>();
     ArrayList<String> listCols = new ArrayList<String>();
     ArrayList<String> report = new ArrayList<String>();

     try {

        String hold_var = new String();
        String hold_var2 = new String();

            while ((field_name = reader.readNext()) != null) 
            {  

                        if(!hold_var.equals(field_name[0]))
                        {
                            listRows.add(field_name[0]);
                            report.add(field_name[2]);
                            // stores from 0
                        }
                        hold_var = field_name[0];

                        if(!hold_var2.equals(field_name[1]))
                        {
                            listCols.add(field_name[1]);

                        }
                        hold_var2 = field_name[1];

            }
        reader.close();     
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    String[][] table = new String[listRows.size()+1][listCols.size()+2];
    table[0][0] = new String(" ");

    int i=0; 

    for ( String str: listRows)
    {

        table[++i][0]= str ;
    }

    i=0;
    for ( String str: report)
    {

        table[++i][1]= str ;
    }

    table[0][1]="report";
    // leaving the first column to fill the fda codes
    for (int cols=2;cols<=listCols.size();cols++)
    {
        table[0][cols] = listCols.get(cols-2);   // we need to traverse from 0

    }

     try {  reader = new CSVReader(new FileReader(args[0]));
        } catch (FileNotFoundException e) { e.printStackTrace();
        }

    try {
            while ((field_name = reader.readNext()) != null) 
            {  

                for ( int rows=0;rows<listRows.size();rows++)
                {

                    if (!field_name[0].equals(table[rows+1][0]))                            
                        continue;     

                    for (int cols=0;cols<listCols.size();cols++)
                    {
                        if(!field_name[1].equals(table[0][cols+2]))
                            continue;
                        table[rows+1][cols+2]=field_name[3].trim();             
                    }
                }

            }

            reader.close();     
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

     PrintWriter pout = null;

     try {
            pout = new PrintWriter(args[1]);
        } catch (FileNotFoundException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }

    for ( int rows=0;rows<listRows.size()+1;rows++)
    {

        for (int cols=0;cols<listCols.size()+1;cols++)
        {

            if(table[rows][cols] == null)
            {
                table[rows][cols]=new String("0");
            }

            // writing to a csv file.
            pout.write(table[rows][cols] +",");
        }
        pout.write("\n");
        pout.flush();
    }

    System.out.print("done");
}

}

另一种选择是使用 library(reshape2) （使用示例） df 来自@richard scriven的帖子）

library(reshape2) 
  as.data.frame(acast(df, V1~V2, value.var="V3", fill=0))
  #       ask death freek frerik hurt lisa pain
  #1234567  13     2    15      0    2    0   10
  #9999999   0    15     0     14    1    2   12

或使用 tidyr ```
library(dplyr)
library(tidyr)

df %>%
spread(V2, V3, fill=0)

V1 ask death freek frerik hurt lisa pain

#1 1234567 13 2 15 0 2 0 10
#2 9999999 0 15 0 14 1 2 12