jennybc

## this is where your .Rprofile should live
R.home(component = "home")

## this is R's main library for add-on packages
.Library

## this shows all the libraries you have
## for newbies, will look same as above
.libPaths()

jennybc

a <- 2
b <- 7
sigSq <- 0.5
n <- 400

set.seed(1234)
x <- runif(n)
y <- a + b * x + rnorm(n, sd = sqrt(sigSq))

(avgX <- mean(x))

jennybc

## Minimal example demonstrating Warning fiasco re: `reorder.factor()` from gdata

## verify a fresh clean search path
search()

## tiny excerpt from some Gapminder data I teach with
foo <- data.frame(country = c("China", "Cuba", "Gambia", "Mali", "Norway"),
                  continent = c("Asia", "Americas", "Africa", "Africa", "Europe"),
                  intercept = c(47.2, 62.2, 28.4, 33.1, 72.2),
                  slope = c(0.53, 0.32, 0.58, 0.38, 0.13))

jennybc

library(testthat)
library(reshape2) # installed from github
                  # SHA 096afb80192f163ced5d001cc416acc1d9a85d12

## working with example from test-melt.r line 132 -->

df <- data.frame(
  id=1:2,
  f1=factor(c("a", "b")),
  f2=factor(c("b", "a"))

jennybc

library(plyr)
library(ggplot2)

gDat <- read.delim("gapminderDataFiveYear.txt")

d_ply(gDat, ~ country, function(z) {
  the_country <- z$country[1]
  the_continent <- z$continent[1]
  
  the_filename <- paste0(the_continent, "_", the_country, ".tsv")

jennybc

library(plyr)

## what's the best way to get tabulation of (days31, oystersOK) into a
## data.frame AND get a grand total row reflecting the expected total of 12
## months?

## related discussion has occured before here:
## http://stackoverflow.com/questions/4946873/how-do-i-add-a-row-to-a-data-frame-with-totals

## related issue open on dplyr:

jennybc

library(dplyr)

## accept default behavior, i.e. stringsAsFactors = TRUE
## downside is that 'name' really shouldn't be a factor
df <- data.frame(name = c("jenny", "jim", "reed", "lorrie"),
                 gender = c("female", "male", "male", "female"))
df %>% group_by(gender) %>% summarize(count = n()) # this works

## protect a single character variable with I()
df <- data.frame(name = I(c("jenny", "jim", "reed", "lorrie")),

jennybc

Lazy evaluation hang nail

Jenny Bryan
18 July, 2014

A group of us at UBC are working through Wickham's Advanced R Programming book together. We just tackled the chapter on Functions, which reminded me of this ...

In the subsection on "Default and missing arguments", we have: "Since arguments in R are evaluated lazily (more on that below), the default value can be defined in terms of other arguments:"

jennybc

---
title: "Wrapper function to open/close graphics device"
author: "Jenny Bryan"
date: "25 July, 2014"
output:
  html_document:
    keep_md: TRUE
---
  
```{r setup, include = FALSE, cache = FALSE}

jennybc

---
title: "twee demo"
author: "Jenny Bryan"
date: "17 August, 2014"
output:
  html_document:
    toc: TRUE
    keep_md: TRUE
---