*/publicclassForTest{publicstaticvoidmain(String[]args){//获取一个指定大小的 List 集合List<Integer>list=getList(1000000);// 开启 for loop 耗时计算long startFor=System.currentTimeMillis();for(int i=0;i<list.size();i++){Integer integer=list.get(i);}long costFor=System.currentTimeMillis()...
labelname:for(initialization;condition;incr/decr){//code to be executed} Java 示例: publicclassLabeledForExample{publicstaticvoidmain(String[] args){ aa:for(inti=1; i <=3; i++) { bb:for(intj=1; j <=3; j++) {if(i ==2&& j ==2) {breakaa; } System.out.println(i +" "+ j...
InJava 8, with the introduction ofFunctional InterfaceΛ’s, Java architects have provided us with an Internal Iterator (forEach loop) supported byCollection frameworkand can be used with the collections object. This method performs a given action for each element of the collection. Let’s see ...
List<Integer>list=getList(1000000);//开启 for loop 耗时计算longstartFor=System.currentTimeMillis();for(inti=0;i<list.size();i++){Integerinteger=list.get(i);}longcostFor=System.currentTimeMillis()-startFor;System.out.println("for loop cost for ArrayList:"+costFor);//forEach 耗时计算long...
System.out.println("for loop traversal cost for ArrayList= "+ forLoopTraversalCost);longforEachStartTime=System.currentTimeMillis();for(Integer integer : mylist) {}longforEachTraversalCost=System.currentTimeMillis()-forEachStartTime; System.out.println("foreach traversal cost for ArrayList= "+ ...
Java for-loop statement is used to iterate over the arrays or collections using a counter variable that is incremented after each iteration.
increment -- code in the body that advances things so we are closer to making the test false. At the end of the body, the code will loop around to the top of the body. Sometimes, some cleanup is required at the end of the body to set things up for the next iteration. In the ab...
普通fori 循环 普通for 循环原理很简单,首先获取集合的长度userList.size(),循环体内根据循环到的下标获取对应的元素, 然后每次循环+1,达到遍历整个集合的目的。 这种写法在以前非常的常见,现在大多使用forEach替代。 代码语言:javascript 代码运行次数:0
* be used with the enhanced for loop. * @since 1.5 */ public interface Iterable<T> { /** * Returns an {@link Iterator} for the elements in * this object. * @return An {@code Iterator} instance. */ Iterator<T> iterator(); ...
Hello again... next code I stuck and can’t find out what’s wrong is import java.util.Scanner; public class Main { public static void main(String[] args) {