Posted By: Akash
I need to count the number of occurrences of a character in a string.
For example, suppose my string contains:
var mainStr = "str1,str2,str3,str4";
I want to find the count of comma
, character, which is 3. And the count of individual strings after the split along comma, which is 4.
I also need to validate that each of the strings i.e str1 or str2 or str3 or str4 should not exceed, say, 15 characters.
I have updated this answer. I like the idea of using a match better, but it is slower:
console.log(("str1,str2,str3,str4".match(/,/g) || ).length); //logs 3 console.log(("str1,str2,str3,str4".match(new RegExp("str", "g")) || ).length); //logs 4
Use a regular expression literal if you know what you are searching for beforehand, if not you can use the
RegExp constructor, and pass in the
g flag as an argument.
null with no results thus the
The original answer I made in 2009 is below. It creates an array unnecessarily, but using a split is faster (as of September 2014). I’m ambivalent, if I really needed the speed there would be no question that I would use a split, but I would prefer to use match.
Old answer (from 2009):
If you’re looking for the commas:
(mainStr.split(",").length - 1) //3
If you’re looking for the str
(mainStr.split("str").length - 1) //4
Both in @Lo’s answer and in my own silly jsperf test split comes ahead in speed, at least in Chrome, but again creating the extra array just doesn’t seem sane.