You can calculate the median of an array of numbers in Ruby in the following steps:

- Sort the array in ascending order;
- Determine the median, which would be
*one*of the following:- Element at the middle index if the array has an odd number of elements, or;
- Average of the two elements at the middle indexes if the array has an even number of elements.

For example, you can implement this in the following way:

def median(arr) return nil if arr.empty? # 1: sort array in ascending order sorted_arr = arr.sort mid_index = sorted_arr.length / 2 # 2.1: if odd, return middle element return sorted_arr[mid_index.floor].to_f if sorted_arr.length.odd? # 2.2: if even, return average of two middle elements return (sorted_arr[mid_index - 1] + sorted_arr[mid_index]).fdiv(2) end print median([1, 2]) #=> 1.5 print median([4, 1, 7]) #=> 4.0 print median([3, 7, 5, 1, 8, 9]) #=> 6.0 print median([39, 3, 14, 29, 23, 13, 23, 23, 40, 23, 21, 5, 7, 12, 56]) #=> 23.0

For arrays with an odd length, rounding down the middle index (i.e. `mid_index.floor`

is needed because dividing an odd array length by `2`

would result in a fraction.

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