Count the occurrence of a character in a string - Javascript

#javascript #algorithms #beginners #tutorial

Solution

function countStringOccurrences(str) {
  let occurrence = {};

  Array.from(str).forEach(char => {
    let currentCount = occurrence[char] || 0;
    occurrence[char] = currentCount + 1;
  });

  console.log(occurrence);
  return occurrence; 
}

countStringOccurrences("hello");
countStringOccurrences("👍😉😉👍");

Result

Object { h: 1, e: 1, l: 2, o: 1 };
Object { 👍: 2, 😉: 2 }

Top comments (5)

Samuel Rouse • Jul 10

This is a nice, simple algorithm. 👍

I would recommend moving occurrence inside the function, as it is currently shared and accumulating changes across multiple calls. You are already returning occurrence from the function, you just aren't using the output directly.

Also, don't be afraid to use longer, clearer names. countStringOccurrences is just fine. When working with an isolated example like this the difference is negligible, but the mental overhead of remembering what all the abbreviations are supposed to mean adds up as the program grows.

Chinwendu Agbaetuo • Jul 10 • Edited

Thanks for your feedback, I have corrected it.

Jon Randy 🎖️ • Jul 10

Unfortunately this doesn't work very well...

Try your function with this string: 😉🏝️👍

countStrOcc('😉🏝️👍')

console.log(occurrence)

{
  "\ud83d": 2,
  "\ude09": 1,
  "\ud83c": 1,
  "\udfdd": 1,
  "️": 1,
  "\udc4d": 1
}

Chinwendu Agbaetuo • Jul 10

I corrected it, thanks.

Chinwendu Agbaetuo • Jul 10

Thanks for testing it, I will look into it.

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Count the occurrence of a character in a string - Javascript

Solution

Result

Top comments (5)

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