Dimitri Tishchenko koozdra

koozdra / key_by_multiple.js

Created August 19, 2020 20:19

key array of objects by multiple keys

	a = [ { name: 'bill', group: 'b' },
	{ name: 'ann', group: 'a' },
	{ name: 'ken', group: 'k' },
	{ name: 'alex', group: 'a' } ]

	_.reduce((sum, v) => {
	const { name, group } = v;
	const current = _.getOr([], [group, name])(sum);
	return _.set([group, name], [...current, v])(sum);
	}, {})(a);

koozdra / psf_q_learning.js

Last active June 18, 2020 05:34

post sign flow q-learning

	shuffle_array = arr =>
	arr
	.map(a => [a, Math.random()])
	.sort(([, lr], [, rr]) => lr - rr)
	.map(([a]) => a);

	user_action_for_state = (state, randy) => {
	if (state === 'p' \|\| state === 'ps' \|\| state === 'psa' \|\| state === 'psam') {
	if (randy < 0.7) {
	return primary_action_names[state[state.length - 1]];

koozdra / shuffle.js

Created June 15, 2020 15:27

javascript shuffle

koozdra / basicbandit.js

Created November 26, 2019 17:58

A basic implementation of bandits for a demo

	const times = require('lodash/fp/times');
	const map = require('lodash/fp/map');
	const sample = require('lodash/fp/sample');
	const maxBy = require('lodash/fp/maxBy');
	const find = require('lodash/fp/find');
	const join = require('lodash/fp/join');
	const flow = require('lodash/fp/flow');
	const get = require('lodash/fp/get');
	const sum = require('lodash/fp/sum');
	const constant = require('lodash/fp/constant');

koozdra / argmaxall.js

Created October 2, 2019 23:20

Get all values that have a max value under a getter

	const a = [
	{ a: 'one', b: 4 },
	{ a: 'two', b: 1 },
	{ a: 'three', b: 4 },
	{ a: 'four', b: 2 }
	];

	function argmaxAll(getterFunction, arr) {
	return reduce(
	([max, arr], curr) => {

koozdra / incremental_mean_reduce.js

Last active April 23, 2019 18:19

koozdra / dice_triplets.js

Last active November 12, 2017 03:47

dice triplets

koozdra / lodash_practice.js

Last active November 11, 2017 16:36

implementing some lodash functions

koozdra / power set

Created November 8, 2017 22:44

Javascript powerset function

	const _ = require('lodash');

	function supersetInner(src) {
	if (src.length === 0) return [];

	const withouts = _.map(src, elem => superset(_.without(src, elem)));
	return [src, ..._.flatten(withouts)];
	}

	function superset(src) {

koozdra / process.js

Created June 7, 2017 16:40

gm image manipulation

	const fs = require('fs');
	const gm = require('gm');

	function getSize(image) {
	return new Promise((resolve, reject) => {
	image.size((err, size) => {
	if (err) {
	reject(err);
	return;
	}