Ruby Flatten Methods
How to create the Own Ruby Flatten method instead of using predefined flatten?
Let’s suppose, you have an array of nested, or multidimensional, arrays, that is, an array in which there are elements that are also arrays:array = [1, [2, 3, [4, 5]]]
The flatten method will return a one-dimensional array, an array where all the values are on the same level:
array = [1, [2, 3, [4, 5]]]
array.flatten #=> [1, 2, 3, 4, 5]
Additionally, you can call the flatten method with an argument, which will flatten that array by that many levels:
array = [1, [2, 3, [4, 5]]]
array.flatten(1) #=> [1, 2, 3, [4, 5]]
Now let’s write our flattening methods!
Flattening an Array by One Dimension
We’re going to start by defining a helper method that flattens an array by one dimension:
def single_flatten(array)
results = []
array.each do |element|
if element.class == Array
element.each {|value| results << value}
else
results << element
end
end
results
end
my_array = [1, [2, 3, [4, 5]]]
single_flatten(my_array) #=> [1, 2, 3, [4, 5]]Flattening an Array n Times
But what if we want to flatten an array a given number of times? We can call single_flatten within a while loop with a counter:
def multiple_flatten(array, n)
count = 0
arr = array
while count < n do
arr = single_flatten(arr)
count += 1
end
arr
end
my_array = [1, [2, 3, [4, [5, 6]]]]
multiple_flatten(my_array, 2) #=> [1, 2, 3, 4, [5, 6]]Flattening an Array with Recursion
Our last helper method is the recursive flatten:
def recursive_flatten(array, results = [])
array.each do |element|
if element.class == Array
recursive_flatten(element, results)
else
results << element
end
end
results
end
my_array = [1, [2, 3, [4, 5]]]
recursive_flatten(my_array) #=> [1, 2, 3, 4, 5]Thanks For Reading..
