JavaScript基础---正则表达式的使用

//去掉左右空格兼容

var str=' ab c ';

var re=/^\s+ | \s+$/g;

if(String.prototype.trim){

console.log(str.trim()+'111')

}else{

console.log(str.replace(re,'')+'222')

}

//2018-07-04转为2018.07.04

//一

var time='2018-07-04'

var arr=time.split('-')

console.log(time.split('-'))

console.log(arr.join('.'))

//二.1

var re=/(\d+)(-)/g;

var s=time.replace(re,function($0,$1,$2){

// console.log($0)

// console.log($1)

// console.log($2)

return $1+'.'

})

//二.2

var re=/-/g

var s=time.replace(re,'.')

console.log(s)

//隐藏手机号中间四位

//一

var phone='15821468110'

var re=/\d{4}/g;

re.lastIndex=3;

// console.log(re.exec(phone)) //['2146']

var s=phone.replace(re.exec(phone),'****')

console.log(s)

//二

var phone='15821468110';

var re=/^(\d{3})(\d{4})(\d{4})$/;

var s=phone.replace(re,function($0,$1,$2,$3){

// console.log($0)

// console.log($1)

// console.log($2)

// console.log($3)

return $1+'****'+$3

})

console.log(s)