jQuery String in String Counting

How to count the number of occurences of a string (subset of characters/regular expression/wildcards) inside another string.

Method 1 – Using a Regular Expression Match


var emails = 'sam@jquery4u.com,admin@jquery4u.com,someone@jquery4u.com',
    count = emails.match(/@/igm).length;
console.log(count);
//output: 3

Word of warning that using .length function on a regular expression which has no matches will result in a null error.


var emails = '',
    count = emails.match(/@/igm).length;
console.log(count);
//output: TypeError: emails.match(/@/gim) is null

If you check the count is not null before assigning the value it does not error and will give you 0 for a no count.

Working Version (null proof):


var emails = 'sam@jquery4u.com,admin@jquery4u.com,someone@jquery4u.com',
    regex = /@/igm,
    count = emails.match(regex),
    count = (count) ? count.length : 0;
console.log(count);
//output: 3

Method 2 – Using a indexOf() Pos Function


function occurrences(string, substring){
    var n=0;
    var pos=0;
    while(true){
        pos=string.indexOf(substring,pos);
        if(pos!=-1){ n++; pos+=substring.length;}
        else{break;}
    }
    return(n);
}
count= occurrences(emails,'@');
console.log(count);
//output: 3

Frequently Asked Questions (FAQs) about jQuery String Counting

How can I count the number of characters in a string using jQuery?

To count the number of characters in a string using jQuery, you can use the .length property. This property returns the number of characters in a string. Here’s an example:

var str = "Hello World!";
var n = str.length;
In this example, n will be 12, because “Hello World!” is 12 characters long, including the space and the exclamation point.

How can I count the number of occurrences of a specific character in a string using jQuery?

To count the number of occurrences of a specific character in a string, you can use the .split() method in combination with the .length property. Here’s an example:

var str = "Hello World!";
var count = (str.split("o").length - 1);
In this example, count will be 2, because the letter “o” appears twice in “Hello World!”.

How can I count the number of words in a string using jQuery?

To count the number of words in a string, you can use the .split() method with a space as the separator, and then use the .length property. Here’s an example:

var str = "Hello World!";
var words = str.split(" ").length;
In this example, words will be 2, because “Hello World!” contains two words.

How can I find the length of a string without using the .length property in jQuery?

If you want to find the length of a string without using the .length property, you can use a loop to iterate through the string until it reaches the end. Here’s an example:

var str = "Hello World!";
var length = 0;
while (str[length] !== undefined)
length++;
In this example, length will be 12, because “Hello World!” is 12 characters long.

How can I count the number of occurrences of a specific word in a string using jQuery?

To count the number of occurrences of a specific word in a string, you can use the .split() method with the word as the separator, and then use the .length property. Here’s an example:

var str = "Hello World! Hello again!";
var count = (str.split("Hello").length - 1);
In this example, count will be 2, because the word “Hello” appears twice in the string.

How can I count the number of sentences in a string using jQuery?

To count the number of sentences in a string, you can use the .split() method with a period, exclamation point, or question mark as the separator, and then use the .length property. Here’s an example:

var str = "Hello World! How are you? I'm fine.";
var sentences = str.split(/[.!?]/).length - 1;
In this example, sentences will be 3, because the string contains three sentences.

How can I count the number of paragraphs in a string using jQuery?

To count the number of paragraphs in a string, you can use the .split() method with two newline characters as the separator, and then use the .length property. Here’s an example:

var str = "Hello World!\n\nHow are you?\n\nI'm fine.";
var paragraphs = str.split("\n\n").length;
In this example, paragraphs will be 3, because the string contains three paragraphs.

How can I count the number of lines in a string using jQuery?

To count the number of lines in a string, you can use the .split() method with a newline character as the separator, and then use the .length property. Here’s an example:

var str = "Hello World!\nHow are you?\nI'm fine.";
var lines = str.split("\n").length;
In this example, lines will be 3, because the string contains three lines.

How can I count the number of vowels in a string using jQuery?

To count the number of vowels in a string, you can use the .match() method with a regular expression that matches vowels, and then use the .length property. Here’s an example:

var str = "Hello World!";
var vowels = (str.match(/[aeiou]/gi) || []).length;
In this example, vowels will be 3, because “Hello World!” contains three vowels.

How can I count the number of consonants in a string using jQuery?

To count the number of consonants in a string, you can use the .match() method with a regular expression that matches consonants, and then use the .length property. Here’s an example:

var str = "Hello World!";
var consonants = (str.match(/[bcdfghjklmnpqrstvwxyz]/gi) || []).length;
In this example, consonants will be 7, because “Hello World!” contains seven consonants.