English word length frequency

english-word-length-frequency.ts

import { exists } from "jsr:@std/fs";
import { map, reduce } from "jsr:@core/iterutil";

const sourceUrl =
  "https://raw.githubusercontent.com/dwyl/english-words/master/words_alpha.txt";
const filename = "words_alpha.txt";

if (!(await exists(filename))) {
  const resp = await fetch(sourceUrl);
  await Deno.writeFile(filename, resp.body!);
}

const content = await Deno.readTextFile(filename);
const samples = content
  .split("\n")
  .filter((v) => v)
  .map((v) => v.trim().length);

function sum(value: number[]): number {
  return value.reduce((a, v) => a + v);
}

function mean(value: number[]): number {
  return sum(value) / value.length;
}

function mode(value: number[]): number {
  const counter = map(
    Map.groupBy(value, (v) => v).entries(),
    ([n, vs]) => [n, vs.length] as const,
  );
  return reduce(counter, (a, v) => a[1] < v[1] ? v : a)![0];
}

function median(value: number[]): number {
  const freq = value.length;
  if (freq % 2 === 0) {
    const mid = freq / 2;
    return (value[mid - 1] + value[mid]) / 2;
  } else {
    const mid = (freq - 1) / 2;
    return value[mid];
  }
}

function quantile(value: number[]): [q1: number, q2: number, q3: number] {
  const freq = value.length;
  if (freq % 2 === 0) {
    const mid = freq / 2;
    const head = value.slice(0, mid);
    const tail = value.slice(mid);
    return [median(head), median(value), median(tail)];
  } else {
    const mid = (freq - 1) / 2;
    const head = value.slice(0, mid);
    const tail = value.slice(mid + 1);
    return [median(head), median(value), median(tail)];
  }
}

console.log(`Frequency: ${samples.length}`);
console.log(`Mean:      ${mean(samples)}`);
console.log(`Mode:      ${mode(samples)}`);
console.log(`Median:    ${median(samples)}`);
console.log(`Quantile:  ${quantile(samples)}`);

const counter = map(
  Map.groupBy(samples, (v) => v).entries(),
  ([n, vs]) => [n, vs.length] as const,
);
console.log("Data:");
for (
  const [n, v] of [...counter].sort(([a], [b]) => a === b ? 0 : a > b ? 1 : -1)
) {
  console.log(`${n.toString().padStart(2)}, ${v}`);
}

https://github.com/dwyl/english-words