locutus/r/stats/weighted_mean.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.weighted_mean = weighted_mean;
const _stats_ts_1 = require("../_helpers/_stats.js");
function weighted_mean(x, w) {
    //      discuss at: https://locutus.io/r/weighted_mean/
    // parity verified: R 4.4
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: JS-safe equivalent of R's weighted.mean().
    //          note 2: Zero weights are skipped, matching R's treatment of zero-weighted values.
    //       example 1: weighted_mean([1, 2, 3])
    //       returns 1: 2
    //       example 2: weighted_mean([1, 2, 3, 4], [1, 1, 1, 2])
    //       returns 2: 2.8
    //       example 3: weighted_mean([1, 2, 3], [0, 0, 1])
    //       returns 3: 3
    const values = (0, _stats_ts_1.toRNumericArray)(x, 'weighted_mean');
    const weights = w === undefined ? values.map(() => 1) : (0, _stats_ts_1.toRNumericArray)(w, 'weighted_mean');
    if (values.length !== weights.length) {
        throw new Error("weighted_mean() 'x' and 'w' must have the same length");
    }
    let weightedTotal = 0;
    let weightTotal = 0;
    for (let index = 0; index < values.length; index += 1) {
        const weight = weights[index] ?? 0;
        if (weight === 0) {
            continue;
        }
        weightedTotal += (values[index] ?? 0) * weight;
        weightTotal += weight;
    }
    return weightedTotal / weightTotal;
}