How to Capitalize Ruby

How to capitalize the first letter in a String in Ruby

It depends on which Ruby version you use:

Ruby 2.4 and higher:

It just works, as since Ruby v2.4.0 supports Unicode case mapping:

"мария".capitalize #=> Мария

Ruby 2.3 and lower:

"maria".capitalize #=> "Maria"
"мария".capitalize #=> мария

The problem is, it just doesn't do what you want it to, it outputs мария instead of Мария.

If you're using Rails there's an easy workaround:

"мария".mb_chars.capitalize.to_s # requires ActiveSupport::Multibyte

Otherwise, you'll have to install the unicode gem and use it like this:

require 'unicode'

Unicode::capitalize("мария") #=> Мария

Ruby 1.8:

Be sure to use the coding magic comment:

#!/usr/bin/env ruby

puts "мария".capitalize

gives invalid multibyte char (US-ASCII), while:

#!/usr/bin/env ruby
#coding: utf-8

puts "мария".capitalize

works without errors, but also see the "Ruby 2.3 and lower" section for real capitalization.

Ruby capitalize every word first letter

try this:

puts 'one TWO three foUR'.split.map(&:capitalize).join(' ')

#=> One Two Three Four

or

puts 'one TWO three foUR'.split.map(&:capitalize)*' '

How to convert a string to lower or upper case in Ruby

Ruby has a few methods for changing the case of strings. To convert to lowercase, use downcase:

"hello James!".downcase    #=> "hello james!"

Similarly, upcase capitalizes every letter and capitalize capitalizes the first letter of the string but lowercases the rest:

"hello James!".upcase      #=> "HELLO JAMES!"
"hello James!".capitalize  #=> "Hello james!"
"hello James!".titleize    #=> "Hello James!" (Rails/ActiveSupport only)

If you want to modify a string in place, you can add an exclamation point to any of those methods:

string = "hello James!"
string.downcase!
string   #=> "hello james!"

Refer to the documentation for String for more information.

Capitalize each word in an array

The documentation for String#capitalise says:

Returns a copy of str with the first character converted to uppercase and the remainder to lowercase.

That's not what you're trying to do. So you need to write something custom instead.

For example:

array.map { |string| string.gsub(/\b[a-z]/, &:upcase) }

I'm not clear if/how you plan to handle other input such as all-caps, or hyphenated words, or multiple lines, ... But if your requirements get more detailed then you may need to expand on this implementation.

Capitalize only first character of string and leave others alone? (Rails)

Titleize will capitalise every word.
This line feels hefty, but will guarantee that the only letter changed is the first one.

new_string = string.slice(0,1).capitalize + string.slice(1..-1)

Update:

irb(main):001:0> string = "i'm from New York..."
=> "i'm from New York..."
irb(main):002:0> new_string = string.slice(0,1).capitalize + string.slice(1..-1)
=> "I'm from New York..."

Capitalize the first letter of each word - Ruby

Do as below using Array#map :

 text.split.map { |i| i.capitalize }.join(' ')

Corrected and short code :

text= "a bunny hops"
final = text.split.map(&:capitalize).join(' ')
puts final
# >> A Bunny Hops

Why didn't your one worked :

Because Array#each method returns the receiver itself on which it has been called :

text= "a bunny hops"
text.split.each(&:capitalize) # => ["a", "bunny", "hops"]

But Array#map returns a new array

text.split.map(&:capitalize) # => ["A", "Bunny", "Hops"]

I would do it as below using String#gsub:

text= "a bunny hops"
text.gsub(/[A-Za-z']+/,&:capitalize) # => "A Bunny Hops"

Note: The pattern I used here with #gsub, is not the trivial one. I did it as per the string have been given in the post itself. You need to change it as per the text string samples you will be having. But the above is a way to do such things with short code and more Rubyish way.

How to make only the first element of a array capitalize in Ruby

Since version 1.9.3, Ruby has had Enumerator#with_index. The method map without a block returns an Enumerator, so you can do the following:

final_title = words.map.with_index do |word, i|
  if i != 0 && (word == "and" || word == "the" || word.length < 3)
    word.downcase
  else
    word.capitalize
  end
end

Clearly, you should make sure your title is lowercase to begin with, or the code checking for "and" and "the" won't work.

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