# Idiom #202 Sum of squares

Calculate the sum of squares s of data, an array of floating point values.

``let s = data.iter().map(|x| x.powi(2)).sum::<f32>();``
``````(defn square [x] (* x x))

(def s (reduce + (map square data)))``````
``````(defn square [x] (* x x))

(def s (->> data (map square) (reduce +)))``````
``````(defn square [x] (* x x))

(def s (transduce (map square) + data))``````
``using System.Linq;``
``var s = data.Sum(x => x * x);``
``var s = data.map((v) => v * v).reduce((sum, v) => sum + v);``
``s = sum( data**2 )``
``import "math"``
``````var s float64
for _, d := range data {
s += math.Pow(d, 2)
}``````
``def s = data.sum { it ** 2 }``
``sumOfSquares = sum . map (^2)``
``s = data.reduce((a, c) => a + c ** 2, 0)``
``import java.util.Arrays;``
``double s = Arrays.stream(data).map(i -> i * i).sum();``
``uses math;``
``````var
data: array of double;
...
s := SumOfSquares(data);
...``````
``use List::Util qw(sum);``
``my \$s = sum map { \$_ ** 2 } @data;``
``s = sum(i**2 for i in data)``
``s = data.sum{|i| i**2}``
``s = data.sum{ _1**2 }``

Bart