To check the repeating digits in a single number in JS-CodePudding

I used random function, to generate a 4 digit number.

The generated 4 digit random number should not be in the sequence of 1111, 2222, 3333, .... The generated random number could be of any number except 1111, 2222, 3333, 4444,..

I used the below approach,

But, i could get the repeating of digits using the below code. Could somebody please help.

function repeatingDigit(n) {
    let num = n.toString();
    for (var i = 0; i <= num.length; i  ) {
       if (num.substr(i) == num.substr(  i)) {
            alert('This pattern can not be used');
        }
       else {
            return parseInt(n);
       }
     }
}
repeatingDigit(Math.floor(1000   Math.random() * 9000));

Thank you.

CodePudding user response：

You could just check if it's divisible by 1111:

function repeatingDigit(n) {
    if (n % 1111 === 0) {
       alert('This pattern can not be used');
    }

    return n;
 }

repeatingDigit(Math.floor(1000   Math.random() * 9000));

CodePudding user response：

You can use a regular expression to test for that:

function repeatingDigit(n) {
    let num = n.toString();
    if (/(\d)\1{3}/.test(num)) {
        alert('This pattern can not be used');
    } else {
        return parseInt(n);
    }
}
repeatingDigit(Math.floor(1000   Math.random() * 9000));

The regular expression /(\d)\1{3}/ tests for digits \d and checks if the following three characters are the same as the first found digit.

CodePudding user response：

You can also use every() function which is inbuilt function provided by javascript to check wheather number is repeated or not after splitting number to array.

function repeatingDigit(num) {
var arr = String(num).split('');
if(arr.every(function (digit) { return digit === arr[0]}))
    return 'Repeated Number!!';
else 
    return num; 
}

console.log(repeatingDigit(Math.floor(1000   Math.random() * 9000)))

Hope This Answer Will Help You! Happy Coding :)