christophergandrud

#' A function to create caterpillar plots from rstan's stanfit objects
#'
#' @param obj a \code{stanfit} object
#' @param pars character string, vector, or regular expression of paramater
#' labels that you would like to plot as declared in \code{model_code} from the
#' \code{\link{stan}} call.
#' @param pars_labels vector of parameter labels. Important: they must be in
#' the same order as in the \code{stanfit} object when \code{as.data.frame(obj)}
#' is called.
#' @param hpd logical. If \code{TRUE} then the 90% and 95% highest probability

christophergandrud

#' Simple function to transform a dependent variable that in [0,1] rather than 
#' (0, 1) to beta regression. Suggested by Smithson & Verkuilen (2006).
#' 
#' @param y vector of the dependent variable that is in [0, 1].

svTransform <- function(y)
{
    n <- length(y)
    transformed <- (y * (n-1) + 0.5)/n
    return(transformed)

christophergandrud

#' Convert text files in a directory to UTF-8 encoding
#' 
#' @param dir a character string naming the directory where the files are located.
#' @param new_dir a character string naming the directory where you would like the
#' converted files to be placed. 
#' 
#' @importFrom dplyr %>%

utf8_convert <- function(dir, new_dir){
    all_files <- list.files(dir)

christophergandrud

########################################
# Download GitHub users with more than 100 followers for Berlin, Brooklyn, 
# and London
# Christopher Gandrud
# 20 October 2014
########################################

library(httr)
library(dplyr)
library(rjson)

christophergandrud

#' Source specific lines in an R file
#'
#' @param file character string with the path to the file to source.
#' @param lines numeric vector of lines to source in \code{file}.

source_lines <- function(file, lines){
    source(textConnection(readLines(file)[lines]))
}

christophergandrud

######################################################## 
# Set up RStudio and JAGS on an Amazon EC2 instance
# Using Ubuntu 64-bit
# Christopher Gandrud
# 16 December 2014
# Partially from http://blog.yhathq.com/posts/r-in-the-cloud-part-1.html 
# See yhat for EC2 instance set up
######################################################## 

# In your terminal navigate to key pair

christophergandrud

christophergandrud

#' Inverse hyperbolic sine transformation
#' 
#' @param x a numeric vector
#' 
#' @details A useful transformation for skewed data that includes 0's and 
#' negative values

ihs <- function(x) {
    transformed <- log(x + sqrt(x ^ x + 1))
    return(transformed)

christophergandrud

#' Convert the output of a topicmodels Latent Dirichlet Allocation to JSON
#' for use with LDAvis
#'
#' @param fitted Output from a topicmodels \code{LDA} model.
#' @param corpus Corpus object used to create the document term
#' matrix for the \code{LDA} model. This should have been create with
#' the tm package's \code{Corpus} function.
#' @param doc_term The document term matrix used in the \code{LDA}
#' model. This should have been created with the tm package's 
#' \code{DocumentTermMatrix} function.

christophergandrud

#' Sets valid working directory from vector of possible directories
#' 
#' @param character vector of possible working directores

set_valid_wd <- function(possible) {
    for (i in possible) {
        if (file.exists(i)) {
            setwd(i)
            message(sprintf('Working directory set as: %s', i))
        }