내가 보려고 올리는 정리

Queue

import java.util.Queue;
import java.util.LinkedList;
Queue<Integer> que = new LinkedList<>();
que.peek();
que.offer(2);
que.poll();

 

List sort

import java.util.Arrays;
Arrays.sort(list);

 

ArrayList

import java.util.ArrayList;

String[] fruitsArray = {"apple", "banana", "kiwi", "mango"};
ArrayList<String> fruits = new ArrayList<>(Arrays.asList(fruitsArray));
fruits.remove(2);
fruits.remove("apple");
fruits.add("pear");
fruits.get(2);
int num = fruits.size();
Collections.sort(answers);

//[ArrayList 탐색]
Iterator it<Integer> = fruits.iterator();
while(it.hasNext()){
	System.out.println(it.next());
    }

String

String array = "abcde";
String num = array.charAt(i);
int size = array.length();
boolean contain = array.contains("aaa");


String [] array2 = {"aaa", "bbb", "ccc"};
array2.indexOf("aaa");

StringBuilder sb = new StringBuilder(str); // 문자열 -> StringBuilder
sb.toString(); //문자열 String으로 변환
sb.substring(3,7); //3번째 인덱스에서 6번째 인덱스까지
sb.append("aaa");
sb.length();
sb.capacity(); //현재 StringBuilder에 할당된 크기를 반환
sb.reverse();

String str = "Hello world!";
String res = str.substring(1, 4);

Stack

Stack<Integer> stack = new Stack<>();
stack.push(5);
stack.pop();
stack.size();
stack.peek();
stack.empty();
stack.search(1);