github.com/MontFerret/ferret@v0.18.0/pkg/stdlib/math/median.go (about)

     1  package math
     2  
     3  import (
     4  	"context"
     5  	"math"
     6  
     7  	"github.com/MontFerret/ferret/pkg/runtime/core"
     8  	"github.com/MontFerret/ferret/pkg/runtime/values"
     9  	"github.com/MontFerret/ferret/pkg/runtime/values/types"
    10  )
    11  
    12  // MEDIAN returns the median of the values in array.
    13  // @param {Int[] | Float[]} array - Array of numbers.
    14  // @return {Float} - The median of the values in array.
    15  func Median(_ context.Context, args ...core.Value) (core.Value, error) {
    16  	err := core.ValidateArgs(args, 1, 1)
    17  
    18  	if err != nil {
    19  		return values.None, err
    20  	}
    21  
    22  	err = core.ValidateType(args[0], types.Array)
    23  
    24  	if err != nil {
    25  		return values.None, err
    26  	}
    27  
    28  	arr := args[0].(*values.Array)
    29  	sorted := arr.Sort()
    30  
    31  	l := sorted.Length()
    32  
    33  	var median core.Value
    34  
    35  	switch {
    36  	case l == 0:
    37  		return values.NewFloat(math.NaN()), nil
    38  	case l%2 == 0:
    39  		median, err = mean(sorted.Slice(l/2-1, l/2+1))
    40  
    41  		if err != nil {
    42  			return values.None, nil
    43  		}
    44  	default:
    45  		median = sorted.Get(l / 2)
    46  	}
    47  
    48  	return median, nil
    49  }