Delete elements from a List using iterator

Question

There is a List<Integer> tabulist that contains values [2,0,5]. Also, there is a List this.getRoutes() which contains keys [0,1,2,3,4,5]. I need to delete elements [2,0,5] from this.getRoutes(). So, as a result I must get the following entries in this.getRoutes():

[1,3,4]

Here is my code:

iter = this.getRoutes().iterator();

while(iter.hasNext())
{
    Route r = iter.next();
    if (tabulist.contains(r.getRouteKey()))
    {
        iter.remove();
    }
}

The problem is that r.getRouteKey() is always 0. Therefore, I am always deleting the first elements from this.getRoutes(). I don't understand why the iterator does not move to [1,2,3,4,5].

How to solve this issue? Maybe I should also delete values from tabulist?

What's wrong with routes = this.getRoutes(); routes.removeAll(tabulist)? — raina77ow
– raina77ow, Commented Nov 13, 2013 at 10:34
@raina77ow Because List<Route> routes contains objects of a class Route. I need to delete the objects on the key "rKey". The values of "rKey" in 6 objects are [0,1,2,3,4,5]. So, I need to delete those objects that have "rKey" equal to [2,0,5] (tabulist). — Klausos Klausos
– Klausos Klausos, Commented Nov 13, 2013 at 10:37
I don't know why the iterator doesn't move forward, but why don't you create a function that accepts two parameters: originalValues and valuesToRemove? In this method create a new result List<Integer> and only fill this with values you want. — Sigur
– Sigur, Commented Nov 13, 2013 at 10:37

Sigur · Accepted Answer · 2013-11-13 11:42:46Z

I didn't test my code, but here are 3 variations on the theme. You should test them in case I made a mistake, but they give an idea of the general idea.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;

public class Class1
{

public static List<int> RemoveItems1(List<int> OriginalValues, List<int> ValuesToRemove)
{
    List<int> result = new List<int>();

    foreach (object item_loopVariable in OriginalValues) {
        item = item_loopVariable;
        if ((!ValuesToRemove.Contains(item))) {
            result.Add(item);
        }
    }

    return result;
}

public static List<int> RemoveItems2(List<int> OriginalValues, List<int> ValuesToRemove)
{
    List<int> result = OriginalValues;

    foreach (object item_loopVariable in ValuesToRemove) {
        item = item_loopVariable;
        if ((OriginalValues.Contains(item))) {
            result.Remove(item);
        }
    }

    return result;
}

public static List<int> RemoveItems3(List<int> OriginalValues, List<int> ValuesToRemove)
{
    List<int> result = OriginalValues;

    foreach (object item_loopVariable in from item1 in ValuesToRemovewhere (OriginalValues.Contains(item1))) {
        item = item_loopVariable;
        result.Remove(item);
    }

    return result;
}
}

The first one adds only elements to get to a result. Like I said in my comment. The second one removes elements from a result that is set to the parameter Originalvalues. The last one is basically the same as number two, but uses LINQ. I'm using static methods because then this can be used in any situation and you don't need to instantiate a class to do this. Which adds extra unnecessary code.

Collectives™ on Stack Overflow

Delete elements from a List using iterator

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related