Get a number of repeated sequences in string

Question

For example, I have a following string that consists of 0 and 1: 1010101101 or anything close to it. How am I able to count number of all repeated 3-number sequences of elements in it? Simple split and regex doesn’t seem to work because when I search for number of repeats of 101 it doesn’t get the right amount. So I guess I need some method to manually iterate through the string with for loop and if’s to check every possible combination. Is there a way to make it faster in case there are much more numbers? I haven’t found any question like that at stackoverflow so I guess it’s not a duplicate. Thank you in advance!

[RegExp match repeated characters](https://stackoverflow.com/questions/6306098/regexp-match-repeated-characters) maybe help you — Mohammad, Apr 17 '19 at 12:39

score 1 · Accepted Answer · answered Apr 17 '19 at 12:50

1

You can use a positive lookahead regex pattern:

var temp = "00111010101101";
var count = (temp.match(/(?=101)/g) || []).length;
console.log(count);

Demo: https://regex101.com/r/JAvzvv/1

answered Apr 17 '19 at 12:50

blhsing

91,368
6
71
106

`"00111010101101".split(101).length - 1` does the same – Slim Apr 17 '19 at 12:52
1

@Slim, no, it doesn’t. In my case it ignores one “101” because it goes right after the previous one. – LionKing Apr 17 '19 at 13:02
So `"10101"` should return 2 not 1 ? – Slim Apr 17 '19 at 13:04

Get a number of repeated sequences in string

1 Answers1