01. 문자열 : 문자열 결합 / 템플릿 문자열
템플릿 문자열은 내장된 표현식을 허용하는 문자열 리터럴이다.
| 번호 | 기본값 | 매서드 | 리턴값 |
|---|---|---|---|
{
//01
{
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;
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;
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.";
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.`;
//나는 모던(modern) 자바스크립트(javascript) 핵심을 배우고 싶다.
}
}
02. toUpperCase() / toLowerCase()
toUpperCase() : 문자열을 대문자로 변경하고, ToLowerCase()는 문자열을 소문자로 변경합니다.
| 번호 | 기본값 | 매서드 | 리턴값 |
|---|---|---|---|
{
// 02
{
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 = str1.toLowerCase();
document.querySelector(".sample02_N2").innerHTML = "2";
document.querySelector(".sample02_Q2").innerHTML = "JAVASCRIPT";
document.querySelector(".sample02_M2").innerHTML = "toLowerCase()";
document.querySelector(".sample02_P2").innerHTML = currentStr2;
}
}
03. trim() / trimStart() / trimEnd()
문자열의 앞/뒤 공백을 제거합니다.
| 번호 | 기본값 | 매서드 | 리턴값 |
|---|---|---|---|
{
// 03
{
const str1 = " javascript ";
const currentStr1 = str1.trim();
document.querySelector(".sample03_N1").innerHTML = "1";
document.querySelector(".sample03_Q1").innerHTML = str1;
document.querySelector(".sample03_M1").innerHTML = "trim()";
document.querySelector(".sample03_P1").innerHTML = currentStr1;
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;
}
}
04. slice() / substring() / substr()
문자열에서 원하는 값을 추출하여 문자열을 반환하는 메서드입니다.
"문자열" .slice(시작위치)
"문자열" .slice(시작위치, 끝나는위치)
//시작 위치의 값은 끝나는 위치 값보다 작아야 합니다.
//substring() 시작값이 끝나는 값보다 클 경우 두 값을 바꿔서 처리(에러 방지) "문자열" .substr(시작위치)
"문자열" .substr(시작위치, 길이)
"문자열" .slice(시작위치, 끝나는위치)
//시작 위치의 값은 끝나는 위치 값보다 작아야 합니다.
//substring() 시작값이 끝나는 값보다 클 경우 두 값을 바꿔서 처리(에러 방지) "문자열" .substr(시작위치)
"문자열" .substr(시작위치, 길이)
{
//04
{
//slice(시작위치)
//slice(시작위치, 끝나는위치)
//시작위치 < 끝나는위치
//substr(시작위치)
//substr(시작위치, 길이)
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); //avs
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
}
}
05. split()
문자열에서 원하는 값을 추출 배열로 반환합니다.
// "문자열".split(구분자);
// "문자열".split(정규식 표현);
// "문자열".split(구분자, 갯수);
// "문자열".split(정규식 표현);
// "문자열".split(구분자, 갯수);
{
//05
{
// "문자열".split(구분자);
// "문자열".split(정규식 표현);
// "문자열".split(구분자, 갯수);
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
}
}
06. replace() / replaceAll()
replace() 메서드는 문자열을 부분 문자열로 구분하고 배열로 반환합니다.
//"문자열".replace("찾을 문자열", "변경할 문자열")
//"문자열".replace(정규식)
//"문자열".replace(정규식, "변경할 문자열")
//"문자열".replace(정규식)
//"문자열".replace(정규식, "변경할 문자열")
{
//"문자열".replace("찾을 문자열", "변경할 문자열")
//"문자열".replace(정규식)
//"문자열".replace(정규식, "변경할 문자열")
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
const currentStr4 =str1.replaceAll("e", "E"); //javascript rEfErEncE
const currentStr5 =str1.replaceAll(/e/g, "E"); //javascript rEfErEncE g는 글로벌의 약자
const currentStr6 =str1.replaceAll(/e/gi, "E"); //javascript rEfErEncE
const str2 = "http://www.naver.com/img01.jpg";
const currentStr7 =str2.replace("img01.jpg","img02.jpg"); //http://www.naver.com/img02.jpg
const str3 = "010-2000-1000";
const currentStr8 = str3.replace("-",""); //0102000-1000
const currentStr9 = str3.replaceAll("-",""); //01020001000
const currentStr10 = str3.replaceAll(/-/g,""); //01020001000
const currentStr11 = str3.replaceAll(/-/g," "); //010 2000 1000
const currentStr12 = str3.replaceAll(/[1-9]/g,"*"); //0*0-*000-*000
console.log(currentStr12);
}
07. concat()
concat() 메서드는 둘 이상의 문자열을 결합하여, 새로운 문자열을 반환합니다.
//"문자열".concat(문자열)
//"문자열".concat(문자열, 문자열....)
//"문자열".concat(문자열, 문자열....)
{
//07
{
//"문자열".concat(문자열)
//"문자열".concat(문자열, 문자열....)
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
console.log(currentStr5);
}
}
08. repeat()
repeat() 메서드는 문자열을 복사하여, 복사한 새로운 문자열을 반환합니다.
{
//08
{
const str1 = "javascript";
const currentStr1 = str1.repeat(0); //''
const currentStr2 = str1.repeat(1); //javascript
const currentStr3 = str1.repeat(2); //javascriptjavascript
}
}
09. padStart() / padEnd()
padStart()/padEnd() 메서드는 주어진 길이에 맞게 앞/뒤 문자열을 채우고, 새로운 문자열을 반환합니다.
//"문자열".padStart(길이)
//"문자열".padStart(길이, 문자열)
//"문자열".padStart(길이, 문자열)
{
//09
{
//"문자열".padStart(길이)
//"문자열".padStart(길이, 문자열)
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
const currentStr11 = str1.padStart(6); // 456
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___
console.log(currentStr22)
}
}
10. indexOf() / lastIndexOf
문자열에서 특정 문자의 위치를 찾고 숫자를 반환합니다.
// "문자열".indexOf(검색값)
// "문자열".indexOf(검색값, 위치값)
// "문자열".lastIndexOf(검색값)
// "문자열".lastIndexOf(검색값, 위치값)
// "문자열".indexOf(검색값, 위치값)
// "문자열".lastIndexOf(검색값)
// "문자열".lastIndexOf(검색값, 위치값)
{
//10
{
// "문자열".indexOf(검색값)
// "문자열".indexOf(검색값, 위치값)
// "문자열".lastIndexOf(검색값)
// "문자열".lastIndexOf(검색값, 위치값)
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("jquery"); //-1
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 str2 = "javascript reference";
const currentStr14 = str1.lastIndexOf("javascript"); //0
const currentStr15 = str1.lastIndexOf("reference"); //11
const currentStr16 = str1.lastIndexOf("j"); //0
const currentStr17 = str1.lastIndexOf("a"); //3
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 기준점 e가1 뒤가 0
const currentStr24 = str1.lastIndexOf("reference", 1); //-1
const currentStr25 = str1.lastIndexOf("reference", 11); //11
const currentStr26 = str1.lastIndexOf("reference", 12); //11
}
}
11. includes() :
includes() 메서드는 문자열 포함 여부를 검색하여, 불린(true, false)을 반환합니다.
// "문자열".includes(검색값);
// "문자열".includes(검색값,시작값);
// "문자열".includes(검색값,시작값);
{
//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
}
}
12. search()
search() 메서드는 문자열(정규식)을 검색하고 위치값(숫자)를 반환합니다.
"문자열".search("검색값");
"문자열".search("정규식 표현");
"문자열".search("정규식 표현");
{
//12 search : 반환(숫자)
{
"문자열".search("검색값");
"문자열".search("정규식 표현");
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("jquery"); //-1
const currentStr7 = str1.search("b"); //-1
const currentStr8 = str1.search(/[a-z]/g); //0
}
}
13. match() : 반환(배열)
match() 메서드는 문자열이 정규식과 매치되는 부분을 검색합니다.
{
//13 match : 반환(배열)
{
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
const currentStr7 = str1.match(/r/g); //['r', 'r', 'r']
const currentStr8 = str1.match(/e/g); //['e', 'e', 'e', 'e']
}
}
14. charAt() / charCodeAt
charAt() 메서드는 지정한 숫자(index)의 단일 문자 값을 반환합니다. charCodeAt()메서드는 지정한 숫자의 유니코드 값을 반환합니다.
"문자열".charAt(숫자);
"문자열".charCodeAt(숫자);
{
// "문자열".charAt("숫자");
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
}
15. startsWith() / endsWith()
startsWith() 메서드는 시작하는 문자열에서 문자열을 검색하여 불린(true, false)으로 반환합니다. endsWith() 메서드는 끝나는 문자열에서 문자열을 검색하여 불린(true, false)으로 반환합니다.
"문자열".startsWith(검색 문자열);
"문자열".startsWith(검색 문자열, 위치값);
"문자열".endsWith(검색 문자열;
"문자열".endsWith(검색 문자열, 시작 위치값);
"문자열".startsWith(검색 문자열, 위치값);
"문자열".endsWith(검색 문자열;
"문자열".endsWith(검색 문자열, 시작 위치값);
{
const str1 = "javscript 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
}