I have an ArrayList of ArrayLists, and I'm trying to access the elements inside, and generally add, remove, replace, and get the items.
My code is below.
import java.io.*;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
public class MarvelNetworkRearrange {
public static void main(String[] args) {
BufferedReader csvReader = null;
try {
String newLine;
ArrayList B = new ArrayList<ArrayList>();
csvReader = new BufferedReader(new FileReader("MARVEL P2P.csv"));
Integer i = 0;
while ((newLine = csvReader.readLine()) != null)
{
B.add(A(newLine));
}
File f = new File("MarvelRearranged.csv");
PrintWriter printWriter = new PrintWriter(f);
ArrayList<String> x = new ArrayList<String>();
x = B.get(0);
x.remove(0);
System.out.println(x);
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
if (csvReader != null) csvReader.close();
}
catch (IOException newException)
{
newException.printStackTrace();
}
}
}
public static ArrayList<String> A(String fromCSV) {
ArrayList<String> csvResult = new ArrayList<String>();
if (fromCSV != null)
{
String[] splitData = fromCSV.split("\\s*,\\s*");
for (int i = 0; i < splitData.length; i++)
{
if (!(splitData[i] == null) || !(splitData[i].length() == 0))
{
csvResult.add(splitData[i].trim());
}
}
}
return csvResult;
}
}
I'm reading in a .csv file, and I'm attempting to rearrange the items in the .csv file in order to create a .csv file that I can use more effectively for a project. However, when I run this code, I get "error: incompatible types: Object cannot be converted to ArrayList" at "x = B.get(0);". I have also tried x.get(0).remove(0).
I am trying to remove the first element of the first ArrayList in the ArrayList B, so what am I doing wrong? The reason I'm trying to remove it is that the specified element is a blank space in the .csv (done intentionally when creating the original, as it was the space between the headers in a matrix).
Please help!
You have defined your ArrayList B
without type, but ArrayList x
has String
type. Either you need to cast the type, or you need to follow below approach which is better:
Specify type of ArrayList B
:
ArrayList<ArrayList<String>> B = new ArrayList<>();
To delete any element from your ArrayList
, skip creating another object and point to an element of B
, directly delete from B
:
B.get(0).remove(0);