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Simple example of converting an Arraylist to a String array and String array to an ArrayList and "adding" an element to a String array
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import java.util.ArrayList; | |
import java.util.Arrays; | |
import java.util.List; | |
public class ArraysSample { | |
public static void main(String[] args) { | |
List<String> list = new ArrayList<>(); // Create an ArrayList of Strings | |
list.add("CSU"); // Add a String to the ArrayList | |
list.add("Global"); // Add a String to the ArrayList | |
System.out.printf("%s%n", list.toString()); // Print the ArrayList [CSU, Global] | |
String[] stringArray = list.toArray(new String[0]); // Convert the ArrayList to an array of Strings | |
System.out.println(stringArray); // Prints the OBJECT, | |
// example: [Ljava.lang.String;@378bf509 | |
System.out.println(Arrays.toString(stringArray)); // Prints the array [CSU, Global] | |
String[][] stringArray2d = {{ "CSU", "Global" }, // Create a 2D array of Strings | |
{ "CSC", "320" }}; | |
System.out.println(Arrays.toString(stringArray2d)); // Prints the OBJECTS in the 2d Array, | |
// example: [[Ljava.lang.String;@5fd0d5ae, | |
// [Ljava.lang.String;@2d98a335] | |
System.out.println(Arrays.deepToString(stringArray2d)); // Prints the 2D array [[CSU, Global], [CSC, 320]] | |
stringArray = addElement(stringArray, "CSC"); // Uses the addElement() method | |
// to add a String to the array. | |
stringArray = addElement(stringArray, "320"); // adds another String to the array. | |
System.out.println(Arrays.toString(stringArray)); // Prints the "modified" array [CSU, Global, CSC, 320] | |
List<String> ArrayList = Arrays.asList(stringArray); // Converts the String array to a List | |
System.out.printf("%s%n", ArrayList.toString()); // Prints the converted List [CSU, Global, CSC, 320] | |
} | |
/** | |
* Method to "add" an element to an immutable array. | |
* @param array the array to add the element to. | |
* @param element the element to add to the array. | |
* @return an array with the element added to it. | |
*/ | |
public static String[] addElement(String[] array, String element) { | |
String[] newArray = new String[array.length + 1]; // Create a new String[] with length +1 | |
System.arraycopy(array, 0, newArray, 0, array.length); // Copy the elements to the new array | |
newArray[newArray.length - 1] = element; // Add the new element to the new array | |
return newArray; // Return the modified new array | |
} | |
} |
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