JAVA

arrayList java

made a mistake @ Felix Riemer

import java.util.ArrayList;

ArrayList<String> dogNames = new ArrayList<String>();
dogNames.add("dog1")

ArrayList in Java

//Requires
import java.util.ArrayList;

// ArrayList<Data_Type> name = new ArrayList<DataType>(Initial_Capacity);
// for Eg :- If Data Type is int (Use it's wrapper class i.e, Integer)
ArrayList<Integer> anything = new ArrayList<Integer>();
// ArrayList is not initialized with zeroes like an array

array arraylist java

// Create
String[] myArray = {"A", "B", "C"};
// constructor no.3, passing a collection
List<String> myArrayList = new ArrayList<>(Arrays.asList("A", "B", "C"));
// Get element
String i = myArray[1];
String j = myArrayList.get(1);
// Get size
int k = myArray.length;     // length is a public field in array, not method.
int l = myArrayList.size();
// Add an element, you can't that w/ array as it is fixed in length
myArrayList.add("D");
// Set an element
myArray[0] = "E";
myArrayList.set(0, "E");
// Remove an element, can't w/ array b/c fixed length
myArrayList.remove(2);  // remove by index
myArrayList.remove("E");    // remove by object

java arraylist

List<String> expenseTypeList = new ArrayList<>();
        expenseTypeList.add("GENERAL");
        expenseTypeList.add("PURCHASE");
        expenseTypeList.add("PROJECT");

arraylist

ArrayList<String>arrayList=new ArrayList<>();

ArrayList

// THIS IS OKAY:
ArrayList arrayList = new ArrayList();

arraylist in java

Size is dynamic
Only supports objects
not syncronized
array based class

array of arraylist in java

// Java code to demonstrate the concept of 
// array of ArrayList
  
import java.util.*;
public class Arraylist {
    public static void main(String[] args)
    {
        int n = 5;
  
        // Here al is an array of arraylist having
        // n number of rows.The number of columns on
        // each row depends on the user.
        // al[i].size() will give the size of the
        // i'th row
        ArrayList<Integer>[] al = new ArrayList[n];
  
        // initializing
        for (int i = 0; i < n; i++) {
            al[i] = new ArrayList<Integer>();
        }
  
        // We can add any number of columns to each
        // rows as per our wish
        al[0].add(1);
        al[0].add(2);
        al[1].add(5);
        al[2].add(10);
        al[2].add(20);
        al[2].add(30);
        al[3].add(56);
        al[4].add(34);
        al[4].add(67);
        al[4].add(89);
        al[4].add(12);
  
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < al[i].size(); j++) {
                System.out.print(al[i].get(j) + " ");
            }
            System.out.println();
        }
    }
}

ArrayList Java

// Java program to demonstrate
// size() method
// for Integer value
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
        try {
  
            // Creating object of ArrayList<Integer>
            ArrayList<Integer>
                arrlist = new ArrayList<Integer>();
  
            // Populating arrlist1
            arrlist.add(1);
            arrlist.add(2);
            arrlist.add(3);
            arrlist.add(4);
            arrlist.add(5);
  
            // print arrlist
            System.out.println("Before operation: "
                               + arrlist);
  
            // getting total size of arrlist
            // using size() method
            int size = arrlist.size();
  
            // print the size of arrlist
            System.out.println("Size of list = "
                               + size);
        }
  
        catch (IndexOutOfBoundsException e) {
  
            System.out.println("Exception thrown: "
                               + e);
        }
    }
}

java arraylist

cat commands_for_c.txt | telnet ...to..c...

arraylist

Collections.sort(list);//sort

Java ArrayList

//ArrayList
ArrayList is a part of collection framework and is present in java.util package. It provides us dynamic arrays in Java. Though, it may be slower than standard arrays but can be helpful in programs where lots of manipulation in the array is needed. 

ArrayList inherits AbstractList class and implements List interface.
ArrayList is initialized by a size, however the size can increase if collection grows or shrunk if objects are removed from the collection.
Java ArrayList allows us to randomly access the list.
ArrayList can not be used for primitive types, like int, char, etc. We need a wrapper class for such cases.
Code to create a generic integer ArrayList : 

ArrayList<Integer> arrli = new ArrayList<Integer>();