regex string match code example
Example 1: javascript regex example match
//Declare Reg using slash
let reg = /abc/
//Declare using class, useful for buil a RegExp from a variable
reg = new RegExp('abc')
//Option you must know: i -> Not case sensitive, g -> match all the string
let str = 'Abc abc abc'
str.match(/abc/) //Array(1) ["abc"] match only the first and return
str.match(/abc/g) //Array(2) ["abc","abc"] match all
str.match(/abc/i) //Array(1) ["Abc"] not case sensitive
str.match(/abc/ig) //Array(3) ["Abc","abc","abc"]
//the equivalent with new RegExp is
str.match('abc', 'ig') //Array(3) ["Abc","abc","abc"]
Example 2: js string to regex
const regex = new RegExp('https:\\/\\/\\w*\\.\\w*.*', 'g');
Example 3: js match any number string
const match = 'some/path/123'.match(/\/(\d+)/)
const id = match[1] // '123'
Example 4: match regex
const regex = /([a-z]*)ball/g;
const str = "basketball football baseball";
let result;
while((result = regex.exec(str)) !== null) {
console.log(result[1]);
// => basket
// => foot
// => base
}
Example 5: how to use the match function in javascript for regex
const str = 'For more information, see Chapter 3.4.5.1';
const re = /see (chapter \d+(\.\d)*)/i;
const found = str.match(re);
console.log(found);
// logs [ 'see Chapter 3.4.5.1',
// 'Chapter 3.4.5.1',
// '.1',
// index: 22,
// input: 'For more information, see Chapter 3.4.5.1' ]
// 'see Chapter 3.4.5.1' is the whole match.
// 'Chapter 3.4.5.1' was captured by '(chapter \d+(\.\d)*)'.
// '.1' was the last value captured by '(\.\d)'.
// The 'index' property (22) is the zero-based index of the whole match.
// The 'input' property is the original string that was parsed.
Example 6: regex exact match
use ^ and $ to match the start and end of your string
^matchmeexactly$