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...
//Code to execute in loop } 1. 2. 3. for循环示例 public class for_loop { public static void main(String[] args) { for (int i = 0; i < 4; i++) { System.out.println("Value of i: " + i); } int j;//declare variable outside for loop if needed beyond loop for (j = ...
*/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...
迭代是所有编程语言中最基本的要求之一,而“ for”是Java中迭代次数最广泛使用的循环。 我们将看到Java for循环迭代技术的发展。 (Java for loop Evolution) We will work on an example for displaying names of actors from aCollection. For the sake of simplicity let’s take aListand set this up: ...
In this tutorial, we’ll cover the four types of loops in Java: the for loop, enhanced for loop (for-each), while loop and do-while loop. We’ll also cover loop control flow concepts with nested loops, labeled loops, break statement, continue statement, return statement and local ...
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...
Java for-loop statement is used to iterate over the arrays or collections using a counter variable that is incremented after each iteration.
For loop: 18907275800 Foreach: 7468100 Iterator: 5632400 ArrayList:在小数量级上,For-loop效率会高一点,For < Iterator < For-each,这里得出的结论根据时间消耗得出,无法仔细比较效率高低,数量级小时,For效率高一点,整体来说,三者速度级别差不多。
1.5中,引入了“泛型(Generics)”机制之后,这个问题才得到了解决。现在可以用Collection< T>来表示全部元素类型都是T的Collection。 转载:http://www.codeceo.com/article/java-for-loop-usage.html 畅享全文阅读体验 扫码后在手机中选择通过第三方浏览器下载...