The array.unshift() method in Ruby is used to fill the array with elements that will begin at the front of the array.
It appends elements passed in as arguments to the front of the original array.
array.unshift(element1, element2, ...elementN)
element1, element2, .. element N: This is the element or elements you want to prepend to the array. It could be one element or more than one.
The value returned is an array with the elements passed as arguments prepended at the front of the array.
In the example below, we will create arrays that are later prepended or filled at the front with elements or values passed as arguments.
# create arraysarr1 = [1, 2, 3, 4, 5]arr2 = ["a", "b", "c", "d", "e"]arr3 = ["Ruby", "Java", "JavaScript", "Python"]arr4 = ["1ab", "2cd", "3ef", "4gh", "5ij"]arr5 = [nil, "nil", "true", "false", true]# prepend arrays with elements with unshift()a = arr1.unshift(6)b = arr2.unshift("e", "f", "g")c = arr3.unshift("C++", "Kotlin")d = arr4.unshift("6kl", "7mn")e = arr5.unshift(false)# print modified arrayputs "#{a}"puts "#{b}"puts "#{c}"puts "#{d}"puts "#{e}"
From the code above, the elements passed as arguments are prepended to the arrays.
The
unshift()method is one of the methods in Ruby that changes the original array.