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cod0216cod0216
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Today I Learned Lambda
1 parent 52330b2 commit 7d60359

22 files changed

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‎lambda/lambda5/filter/FilterMainV1.java‎

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package lambda.lambda5.filter;
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import java.util.ArrayList;
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import java.util.LinkedList;
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import java.util.List;
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public class FilterMainV1 {
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public static void main(String[] args) {
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List<Integer> numbers = List.of(1,2,3,4,5,6,7,8,9,10);
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// 짝수만 거르기
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List<Integer> evenNumbers = filterEvenNumber(numbers);
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System.out.println("evenNumbers = " + evenNumbers);
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// 홀수만 거르기
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List<Integer> oddNumber = filterOddNumber(numbers);
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System.out.println("oddNumber = " + oddNumber);
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}
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private static List<Integer> filterEvenNumber(List<Integer> numbers) {
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List<Integer> filtered = new ArrayList<>();
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for (Integer number : numbers) {
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if(number % 2 == 0) filtered.add(number);
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}
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return filtered;
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}
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private static List<Integer> filterOddNumber(List<Integer> numbers) {
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List<Integer> filtered = new ArrayList<>();
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for (Integer number : numbers) {
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if(number % 2 == 1) filtered.add(number);
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}
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return filtered;
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}
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}

‎lambda/lambda5/filter/FilterMainV2.java‎

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package lambda.lambda5.filter;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.function.Predicate;
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public class FilterMainV2 {
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public static void main(String[] args) {
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List<Integer> numbers = List.of(1,2,3,4,5,6,7,8,9,10);
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Predicate<Integer> isEvenNumber = i -> i%2 == 0;
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// 짝수만 거르기
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List<Integer> evenNumbers = filter(numbers, i -> i % 2 ==0 );
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System.out.println("evenNumbers = " + evenNumbers);
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// 홀수만 거르기
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List<Integer> oddNumber = filter(numbers, i -> i % 2 == 1);
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System.out.println("oddNumber = " + oddNumber);
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}
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private static List<Integer> filter(List<Integer> numbers, Predicate<Integer> predicate) {
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List<Integer> filtered = new ArrayList<>();
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for (Integer number : numbers) {
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if(predicate.test(number)) filtered.add(number);
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}
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return filtered;
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}
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}

‎lambda/lambda5/filter/FilterMainV4.java‎

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package lambda.lambda5.filter;
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import java.util.List;
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import static lambda.lambda5.filter.IntegerFilter.*;
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public class FilterMainV4 {
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public static void main(String[] args) {
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List<Integer> numbers = List.of(1,2,3,4,5,6,7,8,9,10);
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// 짝수만 거르기
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List<Integer> evenNumbers = filter(numbers, i -> i % 2 ==0 );
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System.out.println("evenNumbers = " + evenNumbers);
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// 홀수만 거르기
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List<Integer> oddNumber = filter(numbers, i -> i % 2 == 1);
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System.out.println("oddNumber = " + oddNumber);
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}
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}

‎lambda/lambda5/filter/FilterMainV5.java‎

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package lambda.lambda5.filter;
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import java.util.List;
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import static lambda.lambda5.filter.GenericFilter.filter;
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public class FilterMainV5 {
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public static void main(String[] args) {
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List<Integer> numbers = List.of(1,2,3,4,5,6,7,8,9,10);
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// 짝수만 거르기
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List<Integer> evenNumbers = filter(numbers, i -> i % 2 ==0 );
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System.out.println("evenNumbers = " + evenNumbers);
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// 홀수만 거르기
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List<Integer> oddNumber = filter(numbers, i -> i % 2 == 1);
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System.out.println("oddNumber = " + oddNumber);
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// 문자 사용 필터
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List<String> strings = List.of("A", "BB", "CCC");
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List<String> stringResult = filter(strings, s -> s.length()>=2);
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System.out.println("stringResult = " + stringResult);
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}
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}

‎lambda/lambda5/filter/GenericFilter.java‎

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package lambda.lambda5.filter;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.function.Predicate;
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public class GenericFilter {
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public static <T> List<T> filter(List<T> numbers, Predicate<T> predicate) {
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List<T> filtered = new ArrayList<>();
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for (T number : numbers) {
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if(predicate.test(number)) filtered.add(number);
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}
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return filtered;
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}
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}

‎lambda/lambda5/filter/IntegerFilter.java‎

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package lambda.lambda5.filter;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.function.Predicate;
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public class IntegerFilter {
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public static List<Integer> filter(List<Integer> numbers, Predicate<Integer> predicate) {
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List<Integer> filtered = new ArrayList<>();
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for (Integer number : numbers) {
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if(predicate.test(number)) filtered.add(number);
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}
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return filtered;
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}
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}

‎lambda/lambda5/map/GenericMapper.java‎

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package lambda.lambda5.map;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.function.Function;
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public class GenericMapper {
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public static <T, R> List<R> map(List<T> list, Function<T, R> mapper) {
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List<R> numbers = new ArrayList<>();
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for (T s : list) {
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numbers.add(mapper.apply(s));
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}
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return numbers;
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}
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}

‎lambda/lambda5/map/MapMainV1.java‎

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package lambda.lambda5.map;
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import java.util.ArrayList;
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import java.util.List;
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public class MapMainV1 {
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public static void main(String[] args) {
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List<String> list = List.of("1", "12","123","1234");
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// 문자열을 숫자로 변환
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List<Integer> numbers = mapStringToIntger(list);
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System.out.println("numbers = " + numbers);
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}
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private static List<Integer> mapStringToIntger(List<String> list) {
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List<Integer> numbers = new ArrayList<>();
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for (String s : list) {
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Integer value = Integer.valueOf(s);
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numbers.add(value);
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}
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return numbers;
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}
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}

‎lambda/lambda5/map/MapMainV2.java‎

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package lambda.lambda5.map;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.function.Function;
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public class MapMainV2 {
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public static void main(String[] args) {
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List<String> list = List.of("1", "12","123","1234");
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// 문자열을 숫자로 변환
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List<Integer> numbers = map(list, s -> Integer.valueOf(s));
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System.out.println("numbers = " + numbers);
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}
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private static List<Integer> map(List<String> list, Function<String, Integer> mapper) {
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List<Integer> numbers = new ArrayList<>();
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for (String s : list) {
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numbers.add(mapper.apply(s));
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}
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return numbers;
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}
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}

‎lambda/lambda5/map/MapMainV4.java‎

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package lambda.lambda5.map;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.function.Function;
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import static lambda.lambda5.map.StringToIntegerMapper.map;
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public class MapMainV4 {
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public static void main(String[] args) {
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List<String> list = List.of("1", "12","123","1234");
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// 문자열을 숫자로 변환
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List<Integer> numbers = map(list, s -> Integer.valueOf(s));
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System.out.println("numbers = " + numbers);
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}
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}

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