RUBY

ruby unshift method

irb>> a = [ 0, 1, 2]
=> [0, 1, 2]
irb>> a.unshift('x')
=> ["x", 0, 1, 2]

ruby array unshift

# In Ruby 2.5, append and prepend are implemented as aliases to the original unshift and push methods.
a = ["hello"]
# => ["hello"]
a.append "world"
# => ["hello", "world"]
a.prepend "Hey"
# => ["Hey", "hello", "world"]