LANGUAGE » RUBY

Hash

Last updated:
Reference:docs.ruby-lang.org

Basic ​

Create empty hash:

ruby
my_hash = Hash.new
my_hash = {}

Create filled hash:

ruby
my_hash = {
  'name' => 'Taro',
  'age' => 24
}
my_hash = {
  :name => 'Taro',
  :age => 24
}
my_hash = {
  name: 'Taro',  # Becomes symbol
  age: 24        # Becomes symbol
}

Access values of a hash:

ruby
my_hash['id'] = 1
my_hash[:id] = 1
my_hash.delete(key)

Methods ​

MethodDescription
selectFilter the pairs of key/value.
eachAn iterator for each pair of key/value.
each_keyAn iterator for all keys.
each_valueAn iterator for all values.
keysAn array with only the keys.
valuesAn array with only the values.
empty?true if there are no key/values.
ruby
my_hash.select do |key, value|
  value > 10
end

my_hash.each do |key, value|
  do_something
end

my_hash.each_key do |key|
  do_something
end

my_hash.each_value do |value|
  do_something
end