Javascript

//01. 문자열(string) 결합
const str1 = "자바스크립트";
const str2 = "제이쿼리";

document.querySelector(".sample01_N1").innerHTML = "1";
document.querySelector(".sample01_Q1").innerHTML = "자바스크립트, 제이쿼리";
document.querySelector(".sample01_M1").innerHTML = "문자열(string) 결합";
document.querySelector(".sample01_P1").innerHTML = str1 + str2;

//02. 숫자(number) 결합
const num1 = 100;
const num2 = 200;

document.querySelector(".sample01_N2").innerHTML = "2";
document.querySelector(".sample01_Q2").innerHTML = "100, 200";
document.querySelector(".sample01_M2").innerHTML = "숫자(number) 결합";
document.querySelector(".sample01_P2").innerHTML = num1 + num2;

//03. 문자열(string) 결합
const text1 = "모던";
const text2 = "자바스크립트";
const text3 = "핵심";

document.querySelector(".sample01_N3").innerHTML = "3";
document.querySelector(".sample01_Q3").innerHTML = "모던, 자바스크립트, 핵심";
document.querySelector(".sample01_M3").innerHTML = "문자열(string) 결합";
document.querySelector(".sample01_P3").innerHTML = "나는 " + text1 + "(modern) " +  text2 +"(javascript) " + text3 + "을 배우고 싶다.";

//04. 템플릿 문자열
document.querySelector(".sample01_N4").innerHTML = "4";
document.querySelector(".sample01_Q4").innerHTML = "모던, 자바스크립트, 핵심";
document.querySelector(".sample01_M4").innerHTML = "템플릿 문자열";
document.querySelector(".sample01_P4").innerHTML = `나는 ${text1}(modern) ${text2}(javascript) ${text3}을 배우고 싶다.`;

const str1 = "javascript";
const currentStr1 = str1.toUpperCase();

document.querySelector(".sample02_N1").innerHTML = "1";
document.querySelector(".sample02_Q1").innerHTML = "javascript";
document.querySelector(".sample02_M1").innerHTML = "toUpperCase()";
document.querySelector(".sample02_P1").innerHTML = currentStr1;

const str2 = "JAVASCRIPT";
const currentStr2 = str2.toLowerCase();

document.querySelector(".sample02_N2").innerHTML = "1";
document.querySelector(".sample02_Q2").innerHTML = "JAVASCRIPT";
document.querySelector(".sample02_M2").innerHTML = "toLowerCase()";
document.querySelector(".sample02_P2").innerHTML = currentStr2;

const str1 = "        javascript         ";
const currentStr = str.trim();

document.querySelector(".sample03_N1").innerHTML = "1";
document.querySelector(".sample03_Q1").innerHTML = str1;
document.querySelector(".sample03_M1").innerHTML = "trim()";
document.querySelector(".sample03_P1").innerHTML = currentStr;

const str2 = "        javascript         ";
const currentStr2 = str2.trimStart();

document.querySelector(".sample03_N2").innerHTML = "2";
document.querySelector(".sample03_Q2").innerHTML = str2;
document.querySelector(".sample03_M2").innerHTML = "trimStart()";
document.querySelector(".sample03_P2").innerHTML = currentStr2;

const str3 = "        javascript         ";
const currentStr3 = str3.trimEnd();

document.querySelector(".sample03_N3").innerHTML = "3";
document.querySelector(".sample03_Q3").innerHTML = str3;
document.querySelector(".sample03_M3").innerHTML = "trimEnd()";
document.querySelector(".sample03_P3").innerHTML = currentStr3;

const str1 = "javascript reference";
const currentStr1 = str1.slice(0); //javascript reference
const currentStr2 = str1.slice(1); //avascript reference
const currentStr3 = str1.slice(2); //vascript reference
const currentStr4 = str1.slice(0, 1); //j
const currentStr5 = str1.slice(0, 2); //ja
const currentStr6 = str1.slice(0, 3); //jav
const currentStr7 = str1.slice(1, 2); //a
const currentStr8 = str1.slice(1, 3); //av
const currentStr9 = str1.slice(1, 4); //ava
const currentStr10 = str1.slice(-1); //e
const currentStr11 = str1.slice(-2); //ce
const currentStr12 = str1.slice(-3); //nce
const currentStr13 = str1.slice(-3, -1); //nc
const currentStr14 = str1.slice(-3, -2); //n
const currentStr15 = str1.slice(-3, -3); //

const currentStr16 = str1.slice(1, 4); //ava
const currentStr17 = str1.slice(4, 1); //''
const currentStr18 = str1.substring(1, 4); //ava
const currentStr19 = str1.substring(4, 1); //ava

const currentStr20 = str1.substr(0); //javascript reference
const currentStr21 = str1.substr(1); //avascript reference
const currentStr22 = str1.substr(2); //vascript reference
const currentStr23 = str1.substr(0, 1); //j
const currentStr24 = str1.substr(0, 2); //ja
const currentStr25 = str1.substr(0, 3); //jav
const currentStr26 = str1.substr(1, 2); //av
const currentStr27 = str1.substr(1, 3); //ava
const currentStr28 = str1.substr(1, 4); //avas
const currentStr29 = str1.substr(-1); //e
const currentStr30 = str1.substr(-2); //ce
const currentStr31 = str1.substr(-3); //nce
const currentStr32 = str1.substr(-1, 1); //e
const currentStr33 = str1.substr(-2, 2); //ce
const currentStr34 = str1.substr(-3, 3); //nce

const str1 = "javascript reference";
const currentStr1 = str1.split('');     //['j', 'a', 'v', 'a', 's', 'c', 'r', 'i', 'p', 't', ' ', 'r', 'e', 'f', 'e', 'r', 'e', 'n', 'c', 'e']
const currentStr2 = str1.split(' ');    //['javascript', 'reference']
const currentStr3 = str1.split('', 1); //['j']
const currentStr4 = str1.split('', 2); //['j', 'a']
const currentStr5 = str1.split(' ', 1); //['javascript']
const currentStr6 = str1.split(' ', 2); //['javascript', 'reference']
const currentStr7 = str1.split('j'); //['', 'avascript reference']
const currentStr8 = str1.split('a'); //['j', 'v', 'script reference']
const currentStr9 = str1.split('e'); //['javascript r', 'f', 'r', 'nc', '']

const str2 = "java/script/refer/ence";
const currentStr10 = str2.split('/'); //['java', 'script', 'refer', 'ence']

const str3 = "java&script&refer!ence";
const currentStr11 = str3.split('!'); //['java&script&refer', 'ence']
const currentStr12 = str3.split('&'); //['java', 'script', 'refer!ence']
const currentStr13 = str3.split(/&|\!/); //['java', 'script', 'refer', 'ence']

const str4 = "javascript reference";
const currentStr14 = str4.split('').join(); //j,a,v,a,s,c,r,i,p,t, ,r,e,f,e,r,e,n,c,e
const currentStr15 = str4.split('').join('*'); //j*a*v*a*s*c*r*i*p*t* *r*e*f*e*r*e*n*c*e
const currentStr16 = str4.split('').reverse().join(); //e,c,n,e,r,e,f,e,r, ,t,p,i,r,c,s,a,v,a,j
const currentStr17 = str4.split('').reverse().join('/'); //e/c/n/e/r/e/f/e/r/ /t/p/i/r/c/s/a/v/a/j

const str1 = "javascript reference";
const currentStr1 = str1.replace("javascript", "자바스크립트"); //자바스크립트 reference
const currentStr2 = str1.replace("j", "J"); //Javascript reference
const currentStr3 = str1.replace("e", "E"); //javascript rEference -> 첫 번째 e만 바뀜
const currentStr4 = str1.replaceAll("e", "E"); //javascript rEfErEncE -> replaceAll() 사용하여 모든 e가 바뀜
const currentStr5 = str1.replace(/e/g, "E"); //javascript rEfErEncE -> 정규표현식 사용하여 모든 e가 바뀜. g는 글로벌의 약자
const currentStr6 = str1.replace(/e/gi, "E"); //javascript rEfErEncE -> gi를 사용하면 소문자 대문자 구분하지 않음. 

const str2 = "https://www.naver.com/img01.jpg";
const currentStr7 = str2.replace("img01.jpg", "img02.jpg");

const str3 = "010-0000-1000";
const currentStr8 = str3.replace("-", ""); //0100000-1000
const currentStr9 = str3.replaceAll("-", "");//01000001000
const currentStr10 = str3.replaceAll(/-/g, "");//01000001000
const currentStr11 = str3.replaceAll(/-/g, " ");//010 0000 1000
const currentStr12 = str3.replaceAll(/-/g, "*");//010*0000*1000
const currentStr13 = str3.replace(/[1-9]/g, "*");//0*0-0000-*000

const str1 = "javascript";
const currentStr1 = str1.concat("reference"); //javascriptreference
const currentStr2 = str1.concat(" ", "reference"); //javascript reference
const currentStr3 = str1.concat(", ", "reference"); //javascript, reference
const currentStr4 = str1.concat(", ", "reference", ", ", "book"); //javascript, reference, book
const currentStr5 = str1.concat(",", ["reference", "book"]); //javascript,reference,book

const str1 = "javascript";
const currentStr1 = str1.repeat(0);//''
const currentStr2 = str1.repeat(1);//javascript
const currentStr3 = str1.repeat(2);//javascriptjavascript

const str1 = "456";
const currentStr1 = str1.padStart(1, "0");  //456
const currentStr2 = str1.padStart(2, "0");  //456
const currentStr3 = str1.padStart(3, "0"); //456
const currentStr4 = str1.padStart(4, "0"); //0456
const currentStr5 = str1.padStart(5, "0"); //00456
const currentStr6 = str1.padStart(6, "0");  //000456
const currentStr7 = str1.padStart(6, "1");  //111456
const currentStr8 = str1.padStart(6, "12");  //121456
const currentStr9 = str1.padStart(6, "123");  //123456
const currentStr10 = str1.padStart(6, "1234");  //123456 -> 자릿수 안 맞아서 '4'가 잘림
const currentStr11 = str1.padStart(6);  //   456 -> 앞에 공백으로 처리

const currentStr12 = str1.padEnd(1, "0");  //456
const currentStr13 = str1.padEnd(2, "0");  //456
const currentStr14 = str1.padEnd(3, "0");  //456
const currentStr15 = str1.padEnd(4, "0");  //4560
const currentStr16 = str1.padEnd(5, "0");  //45600
const currentStr17 = str1.padEnd(6, "0");  //456000
const currentStr18 = str1.padEnd(6, "1");  //456111
const currentStr19 = str1.padEnd(6, "12");  //456121
const currentStr20 = str1.padEnd(6, "123");  //456123
const currentStr21 = str1.padEnd(6, "1234");  //456123
const currentStr22 = str1.padEnd(6);  //456___  -> 뒤에 공백으로 처리

const str1 = "javascript reference";
const currentStr1 = str1.indexOf("javascript"); //0
const currentStr2 = str1.indexOf("reference"); //11
const currentStr3 = str1.indexOf("j"); //0
const currentStr4 = str1.indexOf("a"); //1
const currentStr5 = str1.indexOf("v"); //2
const currentStr6 = str1.indexOf("jqudry"); //-1 데이터가 없으면 -1 출력
const currentStr7 = str1.indexOf("b"); //-1
const currentStr8 = str1.indexOf("javascript", 0); //0
const currentStr9 = str1.indexOf("javascript", 1); //-1
const currentStr10 = str1.indexOf("reference", 0); //11
const currentStr11 = str1.indexOf("reference", 1); //11
const currentStr12 = str1.indexOf("reference", 11); //11
const currentStr13 = str1.indexOf("reference", 12); //-1

const currentStr14 = str1.lastIndexOf("javascript"); //0
const currentStr15 = str1.lastIndexOf("reference"); //11
const currentStr16 = str1.lastIndexOf("j"); //0
const currentStr17 = str1.lastIndexOf("a"); //3 ->뒤에서부터 세기 때문에
const currentStr18 = str1.lastIndexOf("v"); //2
const currentStr19 = str1.lastIndexOf("jquery"); //-1
const currentStr20 = str1.lastIndexOf("b"); //-1
const currentStr21 = str1.lastIndexOf("javascript", 0); //0
const currentStr22 = str1.lastIndexOf("javascript", 1); //0
const currentStr23 = str1.lastIndexOf("reference", 0); //-1
const currentStr24 = str1.lastIndexOf("reference", 1); //-1
const currentStr25 = str1.lastIndexOf("reference", 11); //11
const currentStr26 = str1.lastIndexOf("reference", 12); //11

const str1 = "javascript reference";
const currentStr1 = str1.includes("javascript"); //true
const currentStr2 = str1.includes("j"); //true
const currentStr3 = str1.includes("b"); //false
const currentStr4 = str1.includes("reference"); //true
const currentStr5 = str1.includes("reference", 1); //true
const currentStr6 = str1.includes("reference", 11); //true
const currentStr7 = str1.includes("reference", 12); //false

const str1 = "javascript reference";
const currentStr1 = str1.search("javascript"); //0
const currentStr2 = str1.search("reference"); //11
const currentStr3 = str1.search("j"); //0
const currentStr4 = str1.search("a"); //1
const currentStr5 = str1.search("v"); //2
const currentStr6 = str1.search("jqudry"); //-1 데이터가 없으면 -1 출력
const currentStr7 = str1.search("b"); //-1
const currentStr8 = str1.search(/[a-z]/g); //0

const str1 = "javascript reference";
const currentStr1 = str1.match("javascript"); //javascript
const currentStr2 = str1.match("reference"); //reference
const currentStr3 = str1.match("r"); //r
const currentStr4 = str1.match(/reference/); //reference
const currentStr5 = str1.match(/Reference/); //null
const currentStr6 = str1.match(/Reference/i); //reference -> 대소문자 구별x
const currentStr7 = str1.match(/r/g); //['r', 'r', 'r']
const currentStr8 = str1.match(/e/g); //['e', 'e', 'e', 'e']

const str1 = "javascript reference";
const currentStr1 = str1.charAt(); //j
const currentStr2 = str1.charAt("0"); //j
const currentStr3 = str1.charAt("1"); //a
const currentStr4 = str1.charAt("2"); //v

const currentStr5 = str1.charCodeAt();  //106
const currentStr6 = str1.charCodeAt("0");   //106
const currentStr7 = str1.charCodeAt("1");   //97
const currentStr8 = str1.charCodeAt("2");   //118

const str1 = "javascript reference";
const currentStr1 = str1.startsWith('javascript'); //true
const currentStr2 = str1.startsWith('j'); //true
const currentStr3 = str1.startsWith('java'); //true
const currentStr4 = str1.startsWith('reference'); //false
const currentStr5 = str1.startsWith(); //false
const currentStr6 = str1.startsWith(''); //true
const currentStr7 = str1.startsWith('reference', 7); //false
const currentStr8 = str1.startsWith('reference', 11); //true

const currentStr9 = str1.endsWith('reference'); //true
const currentStr10 = str1.endsWith('e'); //true
const currentStr11 = str1.endsWith('refer'); //false
const currentStr12 = str1.endsWith('javascript'); //false
const currentStr13 = str1.endsWith(); //false
const currentStr14 = str1.endsWith(''); //true
const currentStr15 = str1.endsWith('reference', 7); //false
const currentStr16 = str1.endsWith('reference', 20); //true