Entropy: Difference between revisions

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=={{header|Go}}==

===Vlang: Map version===

<lang vlang>import math

import arrays

fn hist(source string) map[string]int {

mut hist := map[string]int{}

for e in source.split('') {

if e !in hist {

hist[e] = 0

}

hist[e]+=1

}

return hist

}

fn entropy(hist map[string]int, l int) f64 {

mut elist := []f64{}

for _,v in hist {

c := f64(v) / f64(l)

elist << -c * math.log2(c)

}

return arrays.sum<f64>(elist) or {-1}

}

fn main(){

input := "1223334444"

h := hist(input)

e := entropy(h, input.len)

println(e)

}</lang>

{{out}}

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