如何检查字符串是否有星号后跟四位数字？

Question

I have a random string which is getting from database. A string might be any length. I need to check whether a string should be in this pattern like *******1234 . A string can have any number of stars (*) with four digit number. How do I check that?

Answer 1

To check if a string starts with asterisks and ends with 4 digits, use this regexp:

 const exp = new RegExp('^\\\\*+\\\\d{4}$'); console.log(exp.test('***1234')) // true; console.log(exp.test('***12345')) // false console.log(exp.test('****234')) // false console.log(exp.test('***d1234')) // false console.log(exp.test('a***1234')) // false 

• ^ : start of string
• \\*+ : match at least one asterisk
• \\d{4} : match exactly 4 digits
• $ : end of string

Answer 2

You can try RegEx /^\\*{1,}\\d{4}/ .

Where

^ starts the matching at the beginning of the string

\\*{1,} matches the character * literally between one and unlimited times, as many times as possible, giving back as needed (greedy)

\\d{4} matches a digit (equal to [0-9]) exactly 4 times

With RegExp.prototype.test() :

The test() method executes a search for a match between a regular expression and a specified string. Returns true or false .

 function checkString(str){ return /^\\*{1,}\\d{4}/.test(str); } console.log(checkString('*******1234')); console.log(checkString('*******12')); console.log(checkString('34*******1234')); 

Answer 3

You can perform the task with two ways, First with regular expression and other with below :

var id = "ctl03_Tabs1";
var lastFive = id.substr(id.length - 5); // => "Tabs1"
var lastChar = id.substr(id.length - 1); // =>