Nguyen Hong Phuc phucnh

Thread Pools

Thread pools on the JVM should usually be divided into the following three categories:

CPU-bound
Blocking IO
Non-blocking IO polling

Each of these categories has a different optimal configuration and usage pattern.

Count empty values in csv file, grouped by column with pandas

Reference: Data Cleaning with Python and Pandas: Detecting Missing Values

Prerequisites

Python 3.6
pip

Running

Applied Functional Programming with Scala - Notes

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

akka-persistenceのプラグインをつくろう

僕はおくみん
@okumin

参考

Persistence — Akka Documentation

	import scala.collection._
	import com.twitter.util._

	scala> val buffer = mutable.ArrayBuffer.empty[Int]
	scala> println(Time.measure { (0 to 50000000).foreach { buffer += _ } }.inMillis)
	17610

	scala> var vector = immutable.Vector.empty[Int]
	scala> println(Time.measure { (0 to 50000000).foreach { vector :+= _ } }.inMillis)
	7865

	#!/usr/bin/env bash

	# lists all unused AWS security groups.
	# a group is considered unused if it's not attached to any network interface.
	# requires aws-cli and jq.

	# all groups
	aws ec2 describe-security-groups \
	\| jq --raw-output '.SecurityGroups[] \| [.GroupName, .GroupId] \| @tsv' \
	\| sort > /tmp/sg.all

	public class Constants {

	/**
	* Contains the path to your Lambda function code.
	*/
	public static final String LAMBDA_TASK_ROOT = System.getenv("LAMBDA_TASK_ROOT");

	/**
	* The environment variable is set to one of the following options, depending on the runtime of the Lambda function:
	* AWS_Lambda_nodejs, AWS_Lambda_nodejs4.3, AWS_Lambda_nodejs6.10

	import scala.slick.lifted.CanBeQueryCondition
	// optionally filter on a column with a supplied predicate
	case class MaybeFilter[X, Y](val query: scala.slick.lifted.Query[X, Y]) {
	def filter[T,R:CanBeQueryCondition](data: Option[T])(f: T => X => R) = {
	data.map(v => MaybeFilter(query.filter(f(v)))).getOrElse(this)
	}
	}

	// example use case
	import java.sql.Date

	// get handle to build output
	def config = new HashMap()
	def bindings = getBinding()
	config.putAll(bindings.getVariables())
	def out = config['out']

	for (aSlave in hudson.model.Hudson.instance.slaves) {
	// check if executor is dead
	execList = aSlave.getComputer().getExecutors()
	for( exec in execList ) {

	// Use Gists to store code you would like to remember later on
	console.log(window); // log the "window" object to the console