Counting upper and lower case characters in a string

Question

First off, I know this is far from professional. I\'m trying to learn how to work with strings. What this app is supposed to do is take a simple text input and do a few thi

Answer 1

Not sure if whole problem, but bad paren on this one

if(text.charAt(letters)) == " " && text(letters) < text.length)
                       ^

Should be

if(text.charAt(letters) == " ") && text(letters) < text.length)
                              ^

And actually I'd make it

if((text.charAt(letters) == " ") && (text(letters) < text.length))

Answer 2

Use regular expressions.

Example

var s = "thisIsAstring";
var numUpper = s.length - s.replace(/[A-Z]/g, '').length;  

// numUpper = 2

Se more at JavaScript replace/regex

Answer 3

Another solution using CharCodeAt() method.

const bigLettersCount = (str) => {
  let result = 0;
  for (let i = 0; i < str.length; i += 1) {
    if (str.charCodeAt(i) > 64 && str.charCodeAt(i) <91 ) {
      result += 1;
    }
   }
   return result
  }

console.log(bigLettersCount('Enter some words.'))

Answer 4

Most of the solutions here will fail when string contains UTF8 or diacritic characters. An improved version that works with all strings can be found at the turbocommons library, here:

https://github.com/edertone/TurboCommons/blob/1e230446593b13a272b1d6a2903741598bb11bf2/TurboCommons-Php/src/main/php/utils/StringUtils.php#L391

Example:

// Returns 2
StringUtils.countByCase('1声A字43B45-_*[]', StringUtils.FORMAT_ALL_UPPER_CASE);

// Returns 1
StringUtils.countByCase('1声A字43B45a-_*[]', StringUtils.FORMAT_ALL_LOWER_CASE);

More info here:

https://turbocommons.org/en/blog/2019-10-15/count-capital-letters-in-string-javascript-typescript-php

Play with it online here:

https://turbocommons.org/en/app/stringutils/count-capital-letters

Answer 5

Another solution is using Array.from() make an array which includes each character of str and then using reduce() to count the number of the uppercase letters.

const str = 'HeLlO';
const res = Array.from(str).reduce((acc, char) => {  
  return acc += char.toUpperCase() === char;
}, 0);

console.log(res);

Answer 6

You can use match() and regular expressions.

var str = "aBcD"; 
var numUpper = (str.match(/[A-Z]/g) || []).length;    // 2