Group_by similar values - Ruby

Question

我想根據值的接近性和值之間的給定間隔將值分組到一個數組中。的5例如

a=[1,2,5,7,20,25,50,53] 

間隔：

a=[[1,2,5,7],[20,25],[50,53]] 

如果我改變的時間間隔爲2：

a=[[1,2],[5,7],[20],[25],[50],[53]] 

伊夫嘗試這種使用group_by但是沒有成功解決。

感謝

Answer 1

我認爲這將做的工作，即使有可能是一個更好的解決方案（如總是Ruby）：

def group array, diff 
    array.sort! # To remove if you're sure your array will always be sorted 
    # array = array.sort # could be a better solution if you don't want your array to be modified in place 
    res = [] 
    subres = [] 

    array.each do |elt| 
    if subres.count == 0 || elt - subres.last <= diff 
     subres << elt 
    else 
     res << subres 
     subres = [elt] 
    end 
    end 
    res << subres unless subres.empty? 
    res 
end 

a = [1, 2, 5, 7, 20, 25, 50, 53] 

p group a, 5 
p group a, 2 

將輸出

[[1, 2, 5, 7], [20, 25], [50, 53]] 
[[1, 2], [5, 7], [20], [25], [50], [53]] 

你通緝。

Answer 2

使用Enumerable#slice_before：

def group(a, n) 
    prev = a.first 
    a.slice_before { |x| 
    (x - prev > n).tap { prev = x } 
    }.to_a 
end 

a = [1,2,5,7,20,25,50,53] 
group(a, 5) # => [[1, 2, 5, 7], [20, 25], [50, 53]] 
group(a, 2) # => [[1, 2], [5, 7], [20], [25], [50], [53]] 

Answer 3

def group(array, interval) 
    result = [[array[0]]] 
    array.inject do |x, y| 
    if y - x <= interval 
     result.last << y 
     else 
     result << [y] 
    end 
    y 
    end 
    result 
end 

a=[1,2,5,7,20,25,50,53] 

p group(a, 5) # => [[1, 2, 5, 7], [20, 25], [50, 53]] 
p group(a, 2) # => [[1, 2], [5, 7], [20], [25], [50], [53]]