# Idiom #201 Euclidean norm

Calculate n, the Euclidean norm of data (an array or list of floating point values).

``n = norm2( data )``
``````func Euclidean(data []float64) float64 {
n := 0.0
for _, val := range data {
n += val * val
}
return math.Sqrt(n)``````
``var n = Math.hypot.apply(null, data)``
``const n = Math.hypot(...data)``
``````double n = 0d;
for(double value : data) {
n += value * value;
}
n = Math.sqrt(n);``````
``uses math;``
``````var
data: array of double;
...
n := norm(data);
...``````
``````use Math::GSL::Vector qw();
use Math::GSL::BLAS qw(gsl_blas_dnrm2);
``````
``````my \$data = [5.0, 4.0, 3.0, 2.0, 1.0];
my \$n = gsl_blas_dnrm2(Math::GSL::Vector->new(\$data)->raw);
``````
``import numpy as np``
``n = np.linalg.norm(data)``
``import numpy as np``
``np.linalg.norm(adata2[:, 0:3] - adata1[ipc1, 0:3], axis=1)``
``require 'matrix'``
``````data = Vector[5.0, 4.0, 3.0, 2.0, 1.0]
n = data.norm``````
``use libm::sqrt;``
``````fn euclidean(data: Vec<f64>) -> f64 {
let mut n = 0.0;
for i in data {
n += i*i;
}
return sqrt(n as f64)
}
let n = euclidean(data);``````
``````data := #( 5 4 3 2 1 ).
n := data squared sum sqrt.``````

Bart