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@navicore
navicore / stdDev.scala.md
Created December 11, 2017 16:47
standard deviation scala
import Numeric.Implicits._

def mean[T: Numeric](xs: Iterable[T]): Double = xs.sum.toDouble / xs.size

def variance[T: Numeric](xs: Iterable[T]): Double = {
  val avg = mean(xs)

  xs.map(_.toDouble).map(a => math.pow(a - avg, 2)).sum / xs.size
}
@kabinpokhrel
kabinpokhrel / server.py
Created December 22, 2017 13:35
Simple HTTP Server Implementation in Python 3
import http.server as httpserver
import socketserver
def main(port=None):
if port is None:
port = 8000
handler = httpserver.SimpleHTTPRequestHandler
try:
httpd = socketserver.TCPServer(("", port), handler)
print("serving at port", port)

Quick Tips for Fast Code on the JVM

I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.

This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea

@rafaotetra
rafaotetra / LC_CTYPE.txt
Created January 8, 2018 11:54 — forked from thanksdanny/LC_CTYPE.txt
Centos warning: setlocale: LC_CTYPE: cannot change locale (UTF-8): No such file or directory
vi /etc/environment
add these lines...
LANG=en_US.utf-8
LC_ALL=en_US.utf-8
object game {
case class Lens[S, A](set: A => S => S, get: S => A) { self =>
def >>> [B](that: Lens[A, B]): Lens[S, B] =
Lens[S, B](
set = (b: B) => (s: S) => self.set(that.set(b)(self.get(s)))(s),
get = (s: S) => that.get(self.get(s))
)
}
case class Prism[S, A](set: A => S, get: S => Option[A]) { self =>
@mattmc3
mattmc3 / modern_sql_style_guide.md
Last active May 22, 2024 06:50
Modern SQL Style Guide
layout author title revision version description
default
mattmc3
Modern SQL Style Guide
2019-01-17
1.0.1
A guide to writing clean, clear, and consistent SQL.

Modern SQL Style Guide

@m0sys
m0sys / build_gdb.sh
Last active December 18, 2023 19:10
Apple M1 ARM GDB Build from Source with Python Support
#!/usr/bin/env sh
# NOTE: First, have to ignore the following warnings to make it build on M1 Chip.
#
# -Wno-constant-logical-operand -Wno-format-nonliteral -Wno-self-assign
#
# To do so the above line should be appended to consts CFLAGS and CXXFLAGS
# under the 'Programs producing files for the HOST machine' section of
# the generated Makefile in dir 'build-gdb'.