Coding problem · Easy · Basics

Capitalize Each Word

Easy Algorithms & data structures

Given a sentence s of lower-case words separated by single spaces, return it with the first letter of each word in upper case.

Example 1

Input: s = "hello world"
Output: "Hello World"

Example 2

Input: s = "ready camel learns fast"
Output: "Ready Camel Learns Fast"

Hints

Hint 1

Split the sentence into words.

Hint 2

Upper-case the first character of each word, keep the rest, then join with spaces.

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Solution and explanation

Show the solution

Time O(n) · Space O(n)

Split on spaces, transform each word (word[0].toUpperCase() + word.slice(1)), and join the words back together.

Reference solution

function capitalizeWords(s) {
  return s.split(' ').map((w) => w.charAt(0).toUpperCase() + w.slice(1)).join(' ');
}

function capitalizeWords(s: string): string {
  return s.split(' ').map((w) => w.charAt(0).toUpperCase() + w.slice(1)).join(' ');
}

def capitalize_words(s: str) -> str:
    return ' '.join(w[:1].upper() + w[1:] for w in s.split(' '))

<?php

function capitalizeWords(string $s): string
{
    return implode(' ', array_map(fn ($w) => ucfirst($w), explode(' ', $s)));
}

class Solution {
    public String capitalizeWords(String s) {
        String[] words = s.split(" ");
        for (int i = 0; i < words.length; i++) {
            if (!words[i].isEmpty()) words[i] = Character.toUpperCase(words[i].charAt(0)) + words[i].substring(1);
        }
        return String.join(" ", words);
    }
}

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