Torvaney

library(tidyverse)
library(rgdal)
library(plotKML)

#Set input and output directories
os50_contours_dir <- here::here("~/Downloads/contours/")
output_dir <- here::here("~/Downloads/kml/")

#Load all shapefiles in input directory
shape_filenames <- list.files(os50_contours_dir, "*line.shp")

Torvaney

# CF: www.coursera.org/learn/ml-clustering-and-retrieval/lecture/aZCHX/optional-improving-efficiency-through-multiple-tables
tibble(x = seq(0, 0.20, 0.001)) %>% 
  crossing(h = 1:4) %>% 
  mutate(single = 1 - (1-x)^h -h*x*(1-x)^(h-1),
         multiple = (1 - (1-x)^h)^(h+1),
         n_lines = h + 1) %>% 
  gather(key, value, -x, -h, -n_lines) %>% 
  ggplot(aes(x = x, y = value, 
             colour = key, group = key)) +
  geom_path() +

Torvaney

tau <- function(hg, ag, home_rates, away_rates, rho) {
  case_when(
    (hg == 0) && (ag == 0) ~ 1 - home_rates * away_rates * rho,
    (hg == 0) && (ag == 1) ~ 1 + home_rates * rho,
    (hg == 1) && (ag == 0) ~ 1 + away_rates * rho,
    (hg == 1) && (ag == 1) ~ 1 - rho,
    TRUE ~ 1
  )
}

Torvaney

(defn print-log
  [x]
  (do
    (if (not (nil? x)) (println x))
    x))

Torvaney

library(rvest)
library(stringr)

webpage <- read_html("https://en.wikipedia.org/wiki/Magic_8-Ball")

# Find the answers
answers <- 
  webpage %>% 
  html_nodes("dd") %>% 
  html_text() %>% 

Torvaney

Torvaney

• https://github.com/mbostock/gistup

Torvaney

---
title: "Compound interest calculator"
---

Terms are defined as:

 * Principal - Initial amount invested
 * Contribution - How much is contributed in each period
 * Interest - Interest rate
 * Period - How frequently interest is compounded

Torvaney

I recently tried hacking some custom "commands" into the R REPL. I thought the method was fun and interesting enough to be worth sharing.

Background

In other language REPLs/interactive prompts, there are often a couple of special commands. Some of the more common ones are exit (to exit the session) and clear (to clear the buffer).

I often find myself instinctively attempting to use these in R. Of course, they do not exist in R. To terminate the R session, one can use quit(...) or q(...), but this requires typing brackets, as well as a "no" if you want to avoid that annoying "save workspace?" prompt.

exit

Torvaney

(defmacro $
  ([x] x)
  ([f x] `(~f ~x))
  ([x f & args] `(~f ($ ~x) ($ ~@args))))

;; Examples
($ 1 + 5)
; 6

($ 1 + 5 + 2)