slice() / substring() / substr()

slice() / substring() / substr() 메서드(문자열 추출)

문자열에서 원하는 값을 추출하여 문자열을 반환하는 메서드입니다.

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01. slice()

"문자열".slice(시작위치)
"문자열".slice(시작위치, 끝나는위치) // 시작 위치의 값은 끝나는 위치 값보다 작아야 합니다.

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);  //''

02. substring()

substring() : 시작값이 끝나는 값보다 클 경우 두 값을 바꿔서 처리(에러 방지)

const str1 = "javascript reference";

const currentStr16 = str1.slice(1, 4);  //ava
const currentStr17 = str1.slice(4, 1);  //''
const currentStr18 = str1.substring(4, 1);  //ava
const currentStr19 = str1.substring(1, 4);  //ava
// substing은 시작위치와 끝나는위치 순서가 바뀌어도 자동으로 바꾸어 출력해줍니다.

03. substr()

"문자열".substr(시작위치)
"문자열".substr(시작위치, 길이)

const str1 = "javascript reference";

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