Java Vector add()
add()是一种Java Vector类方法,用于将指定元素插入给定Vector中。 Java add()方法有两种不同类型,可根据其参数加以区分。这些是:
Java Vector add(int index,E element)方法
Java Vector add(E)方法
Java Vector add(int index,E element)
此方法用于将指定的元素插入给定Vector中的指定位置。
Java Vector add(E e)
此方法将指定的元素附加到此向量的末尾。
语法
以下是
add()方法的声明:
public void add(int index, E element)
public boolean add(E e)
参数
参数 |
说明 |
必需/可选 |
index |
它是要插入指定元素的索引。 |
必需 |
e |
这是将附加到此向量的元素。 |
必需 |
element |
它是将插入到指定位置的元素。 |
必需 |
返回
add(int index,E element)方法不返回任何内容,因为其返回类型为空。
如果成功添加了指定的元素,
add(E e)方法将返回true,否则返回false。
异常
ArrayIndexOutOfBoundsException -如果索引超出范围,此方法将引发异常。
兼容版本
Java 1.2及更高版本
示例1
import java.util.Vector;
public class VectorAddExample1 {
public static void main(String arg[]) {
//Create an empty Vector with an initial capacity of 5
Vector<String> vc = new Vector<>(4);
//Add elements in the vector by using add() method
vc.add("A");
vc.add("B");
vc.add("C");
vc.add("D");
vc.add("E");
//Print all the elements of a Vector
System.out.println("--Elements of Vector are--");
for (String str : vc) {
System.out.println("Alphabet= " +str);
}
}
}
输出:
Alphabet= A
Alphabet= B
Alphabet= C
Alphabet= D
Alphabet= E
示例2
import java.util.Vector;
public class VectorAddExample2 {
public static void main(String arg[]) {
//Create vector object
Vector<String> vr = new Vector<>();
vr.add(0, "Java");
vr.add(1, "Android");
vr.add(2, "Python");
vr.add(3, "lidihuo");
vr.add(4, "Hindi100");
System.out.println("Vector is: " + vr);
}
}
输出:
Vector is: [Java, Android, Python, lidihuo, Hindi100]
示例3
import java.util.Vector;
public class VectorAddExample3 {
public static void main(String arg[]) {
//Create a Vector and add elements
Vector<String> vector = new Vector<>();
vector.add("A");
vector.add("B");
vector.add("C");
vector.add(10,"H");
System.out.println("Elements in Vector : ");
for(int i=0; i < vector.size(); i++)
System.out.println("Element: "+vector.get(i));
}
}
输出:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 10 > 3
at java.base/java.util.Vector.insertElementAt(Vector.java:619)
at java.base/java.util.Vector.add(Vector.java:857)
at myPackage.VectorAddExample3.main(VectorAddExample3.java:11)
示例4
import java.util.Vector;
public class VectorAddExample4 {
public static void main(String arg[]) {
Vector <String> colors = new Vector <String>();
colors.add("White");
colors.add("Green");
colors.add("Black");
colors.add("Pink");
for (String color: colors) {
System.out.println("Element at index: "+colors.indexOf(color) + " Color: " +color);
}
colors.add(1, "Yellow");
System.out.println("New color Yellow added at first position.");
for (String color: colors) {
System.out.println("Element at index: "+colors.indexOf(color) + " Color: " +color);
}
}
}
输出:
Element at index: 0 Color: White
Element at index: 1 Color: Green
Element at index: 2 Color: Black
Element at index: 3 Color: Pink
New color Yellow added at first position.
Element at index: 0 Color: White
Element at index: 1 Color: Yellow
Element at index: 2 Color: Green
Element at index: 3 Color: Black
Element at index: 4 Color: Pink