qoelet

(require '[clojure.string :as string])

(defn is-vowel? [character]
  (contains? #{\a \e \i \o \u} character))

(defn remove-last-vowel [word]
  (defn go [xs flag]
    (cond
      (or (empty? xs) flag)
      xs

qoelet

module Arrows where

import           Control.Arrow
import           System.Directory (doesDirectoryExist)

-- `arr` lifts a function to an arrow
-- arr :: (b -> c) -> a b c

-- e.g. pure function (+ 2) :: Integer -> Integer
-- b :: Integer

qoelet

<?php

class WithFileContents {
  private $resource = null;

  private function open($f) {
    $this->resource = fopen($f, "r");
  }

  public function run($resource, $fun) {

qoelet

total = sum(
    sapply(
        sapply(my_df$ratios, as.character), 
        as.numeric)
    )

qoelet

library(RMySQL)
library(GetoptLong)

# had to work with a secure connection to a MySQL
# make a option file, e.g. opts.cnf
"
[client]
user=kenny
host=mysqldb
ssl-ca=ca.crt

qoelet

# hit a snag time when working with session ids (represented as bigint in a database)

df <- read.csv("myData.csv", header=TRUE) # sid is the column 

"
> tail(df, n=1)$sid
[1] 2e+18
"

# WTF moment

qoelet

CREATE OR REPLACE FUNCTION fa.double_book_keeping_check() RETURNS trigger
AS $$
BEGIN
    IF TG_TABLE_NAME='reports' THEN 
        IF NEW.total_assets = (NEW.total_equity + NEW.total_liabilities) THEN
            RETURN NEW;
        ELSE
            RAISE EXCEPTION 'BOOK KEEPING ERROR: TOTAL ASSETS DOES NOT MATCH SUM(TOTAL LIABILITIES, TOTAL EQUITY)!';
        END IF;
    END IF;

qoelet

# calculating annual maxima from a time series (df)
df$year <- floor_date(df$date, "year")
df_maxima <- ddply(df, "year", summarise, orders=max(orders))
head(arrange(df_maxima, desc(orders), 3) # top 3

qoelet

lhs = reshape([2, -1, 0, -1, 2, -3, 0, -1, 4], 3, 3)
rhs = reshape([0, -1, 4], 3, 1)
soln = lhs\rhs
print((lhs * soln) == rhs) # prove it so

qoelet

# So R can solve linear algebra too!

lhs <- matrix(c(2, -1, 0, -1, 2, -3, 0, -1, 4), nrow=3)
"
     [,1] [,2] [,3]
[1,]    2   -1    0
[2,]   -1    2   -1
[3,]    0   -3    4
"