Introduction to R: Reference

R installation is easy

Library installation is simple (if library is in CRAN)

There are multiple ways of assigning data to a variable

Factors may seem confusing at first, but will prove to be useful

The matrix is just a special array

Lists are useful for collecting objects of various length

Data frames are sort of like lists, but all components have the same length

Most math is what you’d expect it to be, except matrix multiplication

The diag() function is multipurpose (Extract or replace the diagonal of a matrix, or construct a diagonal matrix)

Avoid building a vector/matrix in a loop using concatenation

Looping is faster now than it used to be, but avoiding loops is typically a good idea

ifelse() is a great shortcut if you have a simple statement

Be careful with global variables. Make sure all variables referenced in your function are either fed in or created within the function

fread is much faster and (typically) requires less work. You may benefit from some of the functionalities in the data.table library that should be faster than data.frame manipulations

fread is much faster and (typically) requires less work. You may benefit from some of the functionalities in the data.table library that should be faster than data.frame manipulations