Day3.md

R Fundamentals Day 3

Day1	Day2	Day3	Day4

• R Session for Day 3

• Recap/Questions

• Everything is an object in R - including the language objects, functions, if, while, ....

• lists, data.frames

  • [, [[ and $
  • Data frames and 2-D subsetting

• Can't use logical vector in 1-D list subsetting for [[

  • x[[ c(TRUE, FALSE, TRUE, ... ) ]]
  • Need to use which(). But need to ensure only one or else hierarchical subsetting.
  • Or x [ logicalVector ][[1]]

• factors

  • Subsetting by factors and keeping/dropping levels.

• Vectorization in rnorm(), etc.

  • rnorm(n, mean = vector, sd = vector)

• apply() functions

  • Passing additional arguments
  • Different apply() functions

• try()/tryCatch()

• 2-D subsetting - matrices

• Writing Functions

  • Default values for parameters
  • Idioms
  • warnings and errors

• Debugging

• Writing R Packages

  • Directory structure
  • DESCRIPTION
  • NAMESPACE

• Other Topics