JavaScript 字符串常用操作函数详解与示例

var num=19;
var mystr=num.toString();//"19"

var mystr="l,love,you,Do,you,love,me"
var substr=mystr.split(",");//[l,love,you,Do,you,love,me];
var arrayLimited=mystr.split(",",3);[l,love,you];

var mystr="l,love,you,Do,you,love,me"；
var mystrLength=mystr.length();//25

var mystr="l,love,you,Do,you,love,me"；
var index=mystr.indexOf("you");//7,基于0开始查找，找不到返回-1
var lastindx=mystr.lastIndexOf("you");//14

var mystr="l,love,you,Do,you,love,me";
var replaceStr=mystr.replace("love","hate");//"l,hate,you,Do,you,love,me";
var goreplaceStr=mystr.replace(/love/g,"hate");//"l,hate,you,Do,you,hate,me";
var goreplaceAllStr=mystr.replaceAll("love","hate");//"l,hate,you,Do,you,hate,me";

var mystr="l,love,you,Do,you,love,me";
var char=mystr.charAt(8);//"o";从0开始
var charCode=mystr.charCodeAt(8);//111

var str1="l,love,you";var str="Do,you,love,me!";
var str=str1.contact(str2);

var mystr="l,love,you,Do,you,love,me";
//slice():
var sliceStr=mystr.slice(1,5);//从0开始,",lov"
//substring():
var substring=mystr.substring(1,5);//",lov"
//substr():
var substr=mystr.substr(1,5);//",love"

var myStr = "I,love,you,Do,you,love,me";
var lowCaseStr = myStr.toLowerCase();//"i,love,you,do,you,love,me";
var upCaseStr = myStr.toUpperCase();//"I,LOVE,YOU,DO,YOU,LOVE,ME"

match().接受一个正则的参数
var myStr = "I,love,you,Do,you,love,me";
var pattern="/love/";
var result=mystr.match(pattern);//["love"];
exec()：字符串和字符调换了位置
var myStr = "I,love,you,Do,you,love,me";
var pattern="/love/";
var result=pattern.exec(pattern);
search();匹配到下标
var myStr = "I,love,you,Do,you,love,me";
var pattern = /love/;
var result = myStr.search(pattern);//2

let str = "    Hello   ";
let s = str.trim();
console.log(str); //    Hello
console.log(s); //Hello

let str = "Hello";
let s = str.includes("searchvalue"，number);
console.log(s); //true