Objects in R
Object types: integer, numerical, character, factor, date, logical EDIT AND LOOK UP
Vector: one dimensional array; the elements all have the same type
my_vector <- c(1,2,3,4,5)
my_vector
[1] 1 2 3 4 5
Matrix: two dimensions of same type; ie matrix(c(1:9),byrow = TRUE, nrow = 3) )
my_matrix <- matrix(c(1,2,3,4,5,6,7,8,9), byrow = TRUE, nrow = 3)
my_matrix
[,1] [,2] [,3]
[1,] 1 2 3
[2,] 4 5 6
[3,] 7 8 9
or:
my_matrix <- matrix(c(1:9), byrow = TRUE, nrow = 3)
my_matrix
[,1] [,2] [,3]
[1,] 1 2 3
[2,] 4 5 6
[3,] 7 8 9
Data frame could contain different data types in different columns
List can contain combinations of dataframes, vectors other lists etc
Factors
to be edited
Operators in R
TO BE EDITED:
R operators:
Arithmetic operators
<- = (ie x<-5 define x as number 5)
+ addition (ie: 5+2=7)
– subtraction (ie 5-2=3)
* multiplication (ie 5*3=15)
/ division (ie 6/3=2)
^ exponent (ie 5^2=25)
x %% y modulus (ie 5%%3 =2)
x %/% y integer division (ie 5%/%3=1)
Logical operators
< Less than
<= less than or equal to
> more than
>= more than or equal to
== is equal to
! not
& and
| or
isTRUE(x) is x true? (ie isTRUE(5<4), FALSE)
is.na(x) is ‘not available’ (NA) (ie x<-5, is.na(x), FALSE)
!(is.na(x)) is not ‘not available (NA) (ie x<-5, !(is.na(x)), TRUE)
ifelse(test, yes, no) if test condition is true ‘yes’, otherwise ‘no’
Relational Operators
types and examples
Logical Operators
types and examples
Conditional Operators
types and examples