Наивный Байес

1function naiveBayes(
2  train: Array<[win: 0 | 1, free: 0 | 1, meet: 0 | 1, spam: 0 | 1]>,
3  query: [win: 0 | 1, free: 0 | 1, meet: 0 | 1],
4): { pSpam: number, pHam: number } {
5  const spam = train.filter((r) => r[3] === 1)
6  const ham = train.filter((r) => r[3] === 0)
7 
8  // наивность: признаки независимы — вероятности перемножаются
9  const pSpam = spam.length / train.length *
10    query.reduce((p: number, v: 0 | 1, i: number) => p * ((spam.filter((r) => r[i] === v).length + 1) / (spam.length + 2)), 1)
11  const pHam = ham.length / train.length *
12    query.reduce((p: number, v: 0 | 1, i: number) => p * ((ham.filter((r) => r[i] === v).length + 1) / (ham.length + 2)), 1)
13 
14  return { pSpam, pHam }
15}