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JavaScript: Change the capitalization of all letters in a given string

JavaScript Basic: Exercise-149 with Solution

Write a JavaScript program to change the capitalization of all letters in a given string.

Pictorial Presentation:

JavaScript: Change the capitalization of all letters in a given string.

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Change the capitalization of all letters in a given string.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function change_case(txt) {
    var str1 = "";
    for (var i = 0; i < txt.length; i++) {
        if (/[A-Z]/.test(txt[i])) str1 += txt[i].toLowerCase();
        else str1 += txt[i].toUpperCase();
    }
    return str1;
}

console.log(change_case("w3resource"));
console.log(change_case("Germany"));

Sample Output:

W3RESOURCE
gERMANY

Flowchart:

Flowchart: JavaScript - Change the capitalization of all letters in a given string

ES6 Version:

function change_case(txt) {
    let str1 = "";
    for (let i = 0; i < txt.length; i++) {
        if (/[A-Z]/.test(txt[i])) str1 += txt[i].toLowerCase();
        else str1 += txt[i].toUpperCase();
    }
    return str1;
}

console.log(change_case("w3resource"));
console.log(change_case("Germany"));

Live Demo:

See the Pen javascript-basic-exercise-149 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript program to swap two halves of a given array of integers of even length.
Next: Write a JavaScript program to find the difference of the two given sets.

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JavaScript: Tips of the Day

Returns the sum of the powers of all the numbers from start to end (both inclusive)

Example:

const sumPower = (end, power = 2, start = 1) =>
  Array(end + 1 - start)
    .fill(0)
    .map((x, i) => (i + start) ** power)
    .reduce((a, b) => a + b, 0);
console.log(sumPower(10)); // 385
console.log(sumPower(10, 3)); // 3025
console.log(sumPower(10, 3, 5)); // 2925 

Output:

385
3025
2925