| Data type | Example |
|---|---|
| Integer | 1 |
| Logical | TRUE |
| Numeric | 1.1 |
| String / character | “Red” |
| Factor (enumerated string) | “Amber” or 2 in c(“Red”,“Amber”,“Green”) |
| Complex | i |
| Date | “2015-04-24” |
| Data type | Info | Construction example(s) |
|---|---|---|
| Vector | A 1D set of values of the same data type | c(1,“a”) , 1:3 , LETTERS |
| Matrix | A 2D set of values of the same data type | matrix(LETTERS,nrow=13, ncol=2) , rbind(1:5,2:6) |
| Array | An nD set of values of the same data type | array(LETTERS, c(13,2)) |
| Data.frame | A 2D set of values of different data types | data.frame(a=1:26, b=LETTERS) |
| List | A collection of objects of various data types | list(vector=c(1,“a”), df=data.frame(a=1:6)) |
| Classes | A class is like a formalised list and can also contain functions i.e. methods | Won't be covered in this class |
NB: Most of my work uses vectors, data.tables (a souped up version of data.frames), and lists
| Function | Use |
|---|---|
| is.[data type] | Whether a vector is of a particular type |
| as.[data type] | Attempts to coerce a vector to a data type |
| str | Structure of an object including class/data type, dimensions |
| class | The class(es)/data type(s) an object belongs to |
| summary | Summarises an object |
| dput | Get R code that recreates an object |
| unlist | Simplify a list to a vector |
| dim | Dimensions of a data type |