JavaScript: Find all the possible options to replace the hash in a string
JavaScript Basic: Exercise-116 with Solution
Write a JavaScript program to find all the possible options to replace the hash in a string (Consists of digits and one hash (#)) with a digit to produce an integer divisible by 3.
For a string "2*0", the output should be : ["210", "240", "270"]
Sample Solution:
HTML Code:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title> Find all the possible options to replace the hash in a string</title>
</head>
<body>
</body>
</html>
JavaScript Code:
function is_divisible_by3(mask_str) {
var digitSum = 0,
left = '0'.charCodeAt(),
right = '9'.charCodeAt(),
result = [],
mask_data = mask_str.split(''),
hash_pos = -1;
for (var i = 0; i < mask_data.length; i++) {
if (left <= mask_data[i].charCodeAt() && mask_data[i].charCodeAt() <= right)
{
digitSum += mask_data[i].charCodeAt() - left;
}
else
{
hash_pos = i;
}
}
for (var i = 0; i < 10; i++) {
if ((digitSum + i) % 3 === 0) {
mask_data[hash_pos] = String.fromCharCode(left + i);
result.push(mask_data.join(''));
}
}
return result;
}
console.log(is_divisible_by3("2#0"))
console.log(is_divisible_by3("4#2"))
Sample Output:
["210","240","270"] ["402","432","462","492"]
Flowchart:

ES6 Version:
function is_divisible_by3(mask_str) {
let digitSum = 0;
const left = '0'.charCodeAt();
const right = '9'.charCodeAt();
const result = [];
const mask_data = mask_str.split('');
let hash_pos = -1;
for (var i = 0; i < mask_data.length; i++) {
if (left <= mask_data[i].charCodeAt() && mask_data[i].charCodeAt() <= right)
{
digitSum += mask_data[i].charCodeAt() - left;
}
else
{
hash_pos = i;
}
}
for (var i = 0; i < 10; i++) {
if ((digitSum + i) % 3 === 0) {
mask_data[hash_pos] = String.fromCharCode(left + i);
result.push(mask_data.join(''));
}
}
return result;
}
console.log(is_divisible_by3("2#0"))
console.log(is_divisible_by3("4#2"))
Live Demo:
See the Pen javascript-basic-exercise-116 by w3resource (@w3resource) on CodePen.
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Next: Write a JavaScript program to check if a given matrix is an identity matrix.
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JavaScript: Tips of the Day
Converts a string to title case
Example:
const toTitleCase = str => str .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) .map(x => x.charAt(0).toUpperCase() + x.slice(1)) .join(' '); console.log(toTitleCase('some_database_field_name')); // 'Some Database Field Name' console.log(toTitleCase('Some label that needs to be title-cased')); // 'Some Label That Needs To Be Title Cased' console.log(toTitleCase('some-package-name')); // 'Some Package Name' console.log(toTitleCase('some-mixed_string with spaces_underscores-and-hyphens')); // 'Some Mixed String With Spaces Underscores And Hyphens'
Output:
"Some Database Field Name" "Some Label That Needs To Be Title Cased" "Some Package Name" "Some Mixed String With Spaces Underscores And Hyphens"
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