arr = [1,2,1,3,5,2,4]
如何通过排序按组值计算数组?我需要以下输出:
x[1] = 2
x[2] = 2
x[3] = 1
x[4] = 1
x[5] = 1
arr = [1,2,1,3,5,2,4]
如何通过排序按组值计算数组?我需要以下输出:
x[1] = 2
x[2] = 2
x[3] = 1
x[4] = 1
x[5] = 1
x = arr.inject(Hash.new(0)) { |h, e| h[e] += 1 ; h }