For loop examples in JAVA and Javascript

# For loop examples in JAVA and Javascript ## PH

• 2023-09-10 : First posting.

## TOC ## JAVA Examples ```[.scrollable.lang-java] For (int i=0;i<arr.length;i++) { // do something arr[i], arr[i+1] } char[] charArr="0123456789abcdef".toCharArray(); for (char c: charArr) { // do something System.out.println(c); } Set<String> catsSet=new HashSet<>(); catsSet.add("[Music/Break]--K-pop"); For (String cat: catsSet) { // do something System.out.println(cat); } Collection<String> collection=new ArrayList<String>(); collection.add("zero"); collection.add("one"); collection.add("two"); Iterator<string> iterator=collection.iterator(); // while loop while (iterator.hasNext()) { // do something System.out.println("value= "+iterator.next()); } collection.forEach(System.out::println); // Declaring the LinkedList LinkedList<String> gfg=new LinkedList<String>(); // Appending new elements at // the end of the list gfg.add("Abhishek Rout"); gfg.add("Vaibhav Kamble"); gfg.add("Anupam Kumar"); // for loop for iterating // conditionally through collection System.out.println("Using For loop"); for (Iterator<String> name=gfg.iterator();name.hasNext();) System.out.println("Name : "+name.next()); // while loop for iterating // conditionally through collection System.out.println("\nUsing While Loop"); Iterator<String> name=gfg.iterator(); while (name.hasNext()) System.out.println("Name : "+name.next()); List<String> strList=new ArrayList<String>(); strList.add("list item 1"); strList.add("list item 2"); strList.add("list item 3"); for (int i=0;i<strList.size();i++) { // do something strList.get(i) } ```/ ### Map (HashMap) 출처: , . ```[.scrollable.lang-java] Map<String, String> map=new HashMap<String, String>(); map.put("키1", "값1"); map.put("키2", "값2"); map.put("키3", "값3"); map.put("키4", "값4"); map.put("키5", "값5"); map.put("키6", "값6"); // 방법1 Iterator<String> keys=map.keySet().iterator(); while (keys.hasNext()) { String key=keys.next(); System.out.println(String.format("키:%s, 값:%s", key, map.get(key))); } // 방법2 for (Map.Entry<String, String> elem: map.entrySet()) { System.out.println(String.format("키:%s, 값:%s", elem.getKey(), elem.getValue())); } // 방법3 for (String key: map.keySet()) { System.out.println(String.format("키:%s, 값:%s", key, map.get(key))); } // 방법4 map.forEach((key, value) -> { System.out.println(key+":"+value); }); // 방법5 map.entrySet().stream().forEach(e -> { System.out.println(e.getKey()+":"+e.getValue()); }); // 방법6 map.entrySet().stream().parallel().forEach(e -> { // parallel 은 뭐가 다른거더라??? =ㅇ=;;; // e.getKey() + e.getValue() }); ```/ ## Javascript Examples ```[.scrollable.lang-js] for (let i=0;i<arr.length;i++) { // do something arr[i], arr[i+1] } for (let key in someJSON) { // do something someJSON[key] } const array1 = ['a', 'b', 'c']; for (const element of array1) { console.log(element); } // Expected output: "a" // Expected output: "b" // Expected output: "c" let iterable = "boo"; for (let value of iterable) { console.log(value); } // "b" // "o" // "o" let iterable = new Map([ ["a", 1], ["b", 2], ["c", 3], ]); for (let entry of iterable) { console.log(entry); } // [a, 1] // [b, 2] // [c, 3] for (let [key, value] of iterable) { console.log(value); } // 1 // 2 // 3 let iterable = new Set([1, 1, 2, 2, 3, 3]); for (let value of iterable) { console.log(value); } // 1 // 2 // 3 function* fibonacci() { // 생성기 함수 let [prev, curr] = [1, 1]; while (true) { [prev, curr] = [curr, prev + curr]; yield curr; } } for (let n of fibonacci()) { console.log(n); // 1000에서 수열을 자름 if (n >= 1000) { break; } } // 2 // 3 // 5 // 8 // 13 // 21 // 34 // 55 // 89 // 144 // 233 // 377 // 610 // 987 // 1597 const numbers=[45, 4, 9, 16, 25]; let txt=""; function myFunction(value, index, array) { txt+=value; } numbers.forEach(myFunction); numbers.forEach((value) => { console.log(value); }); ```/ ### Array stored with key, value pair plus ```[.scrollable.lang-js] let a = [1, 2, 3]; a.key = "value" a.key1 = "value1"; for (let e of a) { console.log(e); } // 1 // 2 // 3 // key, value is not iterated. for (let key in a) { console.log(key); } // 0 // 1 // 2 // key // key1 ```/ ## RRA

1. stove99.tistory.com :: Java Map 반복(Iteration)시키는 3가지 방법, 2011-11-13
2. stackoverflow.com :: How do I efficiently iterate over each entry in a Java Map?, 2008-09-05 asked by iMack, 2016-02-22 answered by Slava Vedenin
3. 개발자를 위한 웹 기술 > JavaScript > JavaScript 참고서 > 문 및 선언 > for
4. 개발자를 위한 웹 기술 > JavaScript > JavaScript 참고서 > 문 및 선언 > for...in
5. 개발자를 위한 웹 기술 > JavaScript > JavaScript 참고서 > 문 및 선언 > for...of
6. 개발자를 위한 웹 기술 > JavaScript > JavaScript 참고서 > 표준 내장 객체 > Array > Array.prototype.forEach()