by Sai gowtham

JavaScript − Counting occurrences of a string in string

In this tutorial, we are going to learn about how to count the number of occurrences a particular string in a given string using JavaScript.

Consider we have a string like this.

const str = "hello people, for writing a number of hello ideas"

Now we need to count the number of occurrences of a string hello in the above string.

Using match() method

The match() method accepts the regex as an argument and it returns the array of matched values.

Example:

const str = "hello people, for writing a number of hello ideas"

const count = str.match(/hello/g).length;

console.log(count); // 2

In the above code, we have passed regex /hello/g where g is the global flag which is used to get the array of all occurrences hello in the string instead of first occurrence.

Using split() method

We can also use the split() method to count the number occurrences of a string.

Here is an example:

const str = "hello people, for writing a number of hello ideas"

const count =str.split("hello").length-1; // -1 is important

console.log(count); // 2

In the above code, the split() method splits the string into an array of strings by separating string at each hello character, so that by subtracting the length with -1 we will the get exact count value.

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