A few of Java Iterator and ListIterator examples. 1. Iterator 1.1 Get Iterator from a List or Set, and loop over it. JavaIteratorExample1a.java package com.mkyong; import java.util.Arrays; import java.util.Iterator; import java.util.List; public class JavaIteratorExample1a { public static void main(String[] args) { /* Set<Integer> set = new HashSet<>(); set.add(1); set.add(2); set.add(3); set.add(4); set.add(5); Iterator<Integer> iterator = […]
A simple Java 8 tip to print the Array or List with index in the front. 1. Array with Index Generate the index with IntStream.range. JavaListWithIndex.java package com.mkyong.java8; import java.util.List; import java.util.stream.Collectors; import java.util.stream.IntStream; public class JavaArrayWithIndex { public static void main(String[] args) { String[] names = {"Java", "Node", "JavaScript", "Rust", "Go"}; List<String> collect = […]
This article shows you different ways to print a name ten times. 1. Looping 1.1 For loop JavaSample1.java package com.mkyong.samples; public class JavaSample1 { public static void main(String[] args) { for (int i = 0; i < 10; i++) { System.out.println("Java "); } } } Output Java Java Java Java Java Java Java Java Java […]
Here’s a Java example to print a name 1000 times without looping or recursion, instead, use String concatenation and simple math. Just for fun. JavaNoLoop.java package com.mkyong.samples; public class JavaNoLoop { public static void main(String[] args) { String s1 = "Mkyong\n"; String s3 = s1 + s1 + s1; String s10 = s3 + s3 […]
In this tutorial, we are going to learn how to add / concatenate two lists in Python. What Is Concatenation? Concatenation of lists is an operation where the elements of one list are added at the end of another list. For example, if we have a list with elements [1, 2, 3] and another list […]
Call the .values() method of the enum class to return an array, and loop it with the for loop: for (EnumClass obj : EnumClass.values()) { System.out.println(obj); } For Java 8, convert an enum into a stream and loop it: Stream.of(EnumClass.values()).forEach(System.out::println); 1. For Loop Enum 1.1 An enum to contain a list of the popular JVM […]
Python example to print the key value of a dictionary. stocks = { ‘IBM’: 146.48, ‘MSFT’: 44.11, ‘CSCO’: 25.54 } print(stocks) for k, v in stocks.items(): print(k, v) for k in stocks: print(k, stocks[k]) Output {‘IBM’: 146.48, ‘MSFT’: 44.11, ‘CSCO’: 25.54} IBM 146.48 MSFT 44.11 CSCO 25.54 IBM 146.48 MSFT 44.11 CSCO 25.54 References Python […]
In Java, there are 3 ways to loop or iterate a HashMap 1. If possible, always uses the Java 8 forEach. Map<String, String> map = new HashMap<>(); map.forEach((key, value) -> System.out.println("[Key] : " + key + " [Value] : " + value)); 2. Normal for loop in entrySet() Map<String, String> map = new HashMap<>(); for […]
In JavaScript, we can use for, forEach or for..of to loop an Array. 1.1 for //old-school, classic for loop var str = ["a", "b", "c", "d", "e"]; for(var i =0; i < str.length; i++){ console.log(str[i]); //a,b,c,d,e } output a b c d e 1.2 forEach() var num = [1, 2, 3, 4, 5]; num.forEach(anyFunction) function […]
In JavaScript, we can use forEach(function) to loop an Array. The provided function in forEach() will run once for each array element. var total = 0; var num = [1, 2, 3, 4, 5]; num.forEach(anyFunction) function anyFunction(data){ total += data; } console.log(total); //15 var words = ""; var num = ["a", "b", "c", "d", "e"]; […]
A JMH benchmark test about Forward loop vs Reverse loop for a List. There is a myth about reverse loop is faster, is this true? Tested with JMH 1.21 Java 10 Maven 3.6 CPU i7-7700 Forward loop for (int i = 0; i < aList.size(); i++) { String s = aList.get(i); System.out.println(s); } Reverse loop […]
Benchmark (N) Mode Cnt Score Error Units BenchmarkLoop.loopFor 10000000 avgt 10 61.673 ± 1.251 ms/op BenchmarkLoop.loopForEach 10000000 avgt 10 67.582 ± 1.034 ms/op BenchmarkLoop.loopIterator 10000000 avgt 10 66.087 ± 1.534 ms/op BenchmarkLoop.loopWhile 10000000 avgt 10 60.660 ± 0.279 ms/op In Java, we can use JMH (Java Microbenchmark Harness) framework to measure the performance of a […]
In this tutorial, we will show you how to use for-in-loop to loop a List in Python. #example 1 frameworks = [‘flask’, ‘pyramid’, ‘django’] #list for temp in frameworks: print temp print "Python framework : %s" %temp #example 2 numbers = [2,4,6,8,10] #list for num in numbers: print num print "Number : %d" %num Output […]
In this tutorial, we will show you how to loop a dictionary in Python. 1. for key in dict: 1.1 To loop all the keys from a dictionary – for k in dict: for k in dict: print(k) 1.2 To loop every key and value from a dictionary – for k, v in dict.items(): for […]
No nonsense, four ways to loop ArrayList in Java For loop For loop (Advance) While loop Iterator loop package com.mkyong.core; import java.util.ArrayList; import java.util.Iterator; import java.util.List; public class ArrayListLoopingExample { public static void main(String[] args) { List<String> list = new ArrayList<String>(); list.add("Text 1"); list.add("Text 2"); list.add("Text 3"); System.out.println("#1 normal for loop"); for (int i = […]
Here i show you four ways to loop a List in Java. Iterator loop For loop For loop (Adcance) While loop package com.mkyong.core; import java.util.Arrays; import java.util.Iterator; import java.util.List; public class ArrayToList { public static void main(String[] argv) { String sArray[] = new String[] { "Array 1", "Array 2", "Array 3" }; // convert array […]
Node This article is using the endTime – startTime method to measure the performance of a loop, it ignores the JVM warm up optimization, the result may not consistent or accurately. A better way is using the OpenJDK JMH framework to do the benchmark testing, because it will take care of the JVM warm up […]
Node This article is using the endTime – startTime method to measure the performance of a loop, it ignores the JVM warm up optimization, the result may not consistent or accurately. A better way is using the OpenJDK JMH framework to do the benchmark testing, because it will take care of the JVM warm up […]
