String to Uppercase in Ruby

Capitalize the first letter with capitalize

A string in Ruby is a simple text between ‘ ‘ or between ” “. It fits on one line. As an example:

  "Hello world"

To modify this string and put the first letter in uppercase, there is the capitalize function:

  puts "hello world".capitalize
  // output: "Hello world"

Whatever the starting state of the string, the ending state will always be the same:

  puts "HELLO WORLD".capitalize
  // output: "Hello world"

  puts "hello World".capitalize
  // output: "Hello world"

Attention, if there is a number at the beginning of the string, this gives:

  puts "2 hello world".capitalize
  // output: "2 hello world"

  puts "2 HELLO WORLD".capitalize
  // output: "2 hello world"

Capitalize the entire string with upcase

The upcase function will help you to modify the string and put all the letters in uppercase:

  puts "hello world".upcase
  // output: "HELLO WORLD"

Whatever the starting state of the string, the ending state will always be the same:

  puts "Hello World".upcase
  // output: "HELLO WORLD"

In addition, I invite you to read my article on how to lowercase a string in Ruby.