datalove / caret_nnet_ANN

Last active August 29, 2015 14:23

Basic usage of 'caret' package with artificial neural net from 'nnet' package


	#########################
	# find and load packages
	#########################

	install.packages(c("nnet","caret"))
	library(caret)

	###################
	# Build neural net

datalove / in_place_sub.R

Last active August 29, 2015 14:25

In-place string substitution in R. Example: s("my name is $x and time is $y")

	s <- function(str) {

	require(stringr)
	require(magrittr)

	# helper functions
	get_vars <- function(str) str %>% str_extract_all("\\$[a-zA-Z0-9_\\.]+") %>% unlist %>% str_replace_all("\\$","")
	eval_var <- function(var) eval(parse(text = var)))
	add_token <- function(var) paste0("\\$", var)

datalove / xlsxToR.r

Last active August 29, 2015 14:27 — forked from schaunwheeler/xlsxToR.r

Import an xlsx file into R by parsing the file's XML structure.

	# The MIT License (MIT)
	#
	# Copyright (c) 2012 Schaun Jacob Wheeler
	#
	# Permission is hereby granted, free of charge, to any person obtaining a copy
	# of this software and associated documentation files (the "Software"), to deal
	# in the Software without restriction, including without limitation the rights
	# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	# copies of the Software, and to permit persons to whom the Software is
	# furnished to do so, subject to the following conditions:

datalove / xl_col_to_num.R

Last active August 29, 2015 14:28

R function to convert excel column names ('Q','AD', etc) to numbers

	xl_col_to_num <- function(column) {

	# calc value for a letter given its position i
	# eg for'CZ', C's contrib is 26^(1-1)3 and Z's contrib is 26^(2-1)26
	calc_pos_val <- function(x,i) 26^(i-1) * which(LETTERS == x)

	# for a single column like 'CZ', calc each positional value and sum the total
	single_col <- function(x) calc_pos_val %>% mapply(x, rev(seq_along(x)) ) %>% sum()

	column %>%

datalove / vectorised_hash_tables.R

Created August 25, 2015 03:21

Fast lookups using R's evironments, which are implemented using hash tables (vectorised)

	# inspired by https://stackoverflow.com/questions/16782518/is-this-a-good-way-to-make-a-multi-dimensional-dictionary-in-r/16782745#16782745
	# and http://broadcast.oreilly.com/2010/03/lookup-performance-in-r.html

	hash <- function( ) {
	new.env( hash = TRUE, parent = emptyenv() )
	}

	set <- function(key, val, hash) {
	invisible(mapply(assign, key, val, MoreArgs = list(envir = hash)))
	}

datalove / xpath_selection.md

Last active August 26, 2015 00:03

XPath to select parent where children meet certain criteria

For the code below, if we want to select records have a field with colour = Red and length > 30...

<root>
<record id="1">
  <field id="colour" value="Red" />
  <field id="size"   value="Small" />
  <field id="length" value=25 />
</record>

datalove / preso.R

Created September 9, 2015 22:54

R preso for WARG

	```{r, echo = FALSE}
	library(knitr)
	library(plyr)
	library(data.table)
	library(dplyr)

	gears <- mtcars$gear
	mtcars <- mtcars[,1:6]
	mtcars$gear <- gears

datalove / ROracle_OSX.md

Last active December 2, 2017 02:01

ROracle on OS X

Running ROracle on OSX

Installing Oracle Instant Client

Go to http://www.oracle.com/technetwork/topics/intel-macsoft-096467.html and look for something like this:

Instant Client Package - Basic: All files required to run OCI, OCCI, and JDBC-OCI applications Download instantclient-basic-macos.x64-11.2.0.4.0.zip (62,794,903 bytes)

Once the file is downloaded, follow the instructions at the bottom of the download page (reproduced below)

Mia datalove

Running ROracle on OSX

Installing Oracle Instant Client