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JavaScript: Number of occurrences of each letter in specified string

JavaScript Function: Exercise-17 with Solution

Write a JavaScript function to get the number of occurrences of each letter in specified string.

Pictorial Presentation:

JavaScript:  Number of occurrences of each letter in specified string

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Number of occurrences of each letter in specified string</title>
</head>
<body>

JavaScript Code:

function Char_Counts(str1) {
var uchars = {};
str1.replace(/\S/g, function(l){uchars[l] = (isNaN(uchars[l]) ? 1 : uchars[l] + 1);});
return uchars;
}
console.log(Char_Counts("The quick brown fox jumps over the lazy dog"));

Sample Output:

{"T":1,"h":2,"e":3,"q":1,"u":2,"i":1,"c":1,"k":1,"b":1,"r":2,"o":4,"w":1,"n":1,"f":1,"x":1,"j":1,"m":1,"p":1,"s":1,"v":1,"t":1,"l":1,"a":1,"z":1,"y":1,"d":1,"g":1}

Flowchart:

Flowchart: JavaScript function: Number of occurrences of each letter in a string

Live Demo:

See the Pen JavaScript - Number of occurrences of each letter in specified string-function-ex- 17 by w3resource (@w3resource) on CodePen.


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Next: Write a function for searching JavaScript arrays with a binary search.

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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv