R Primitives

Vectors

Use the typeof function to explore the data structure's low-level structure, and the class object to see the object's higher level structure.



In [ ]:

    
random_norms <- rnorm(100)
typeof(random_norms)
class(random_norms)

some_letters <- letters[1:10]
typeof(some_letters)
class(some_letters)

int_vector <- c(1L, 2L, 3L)
typeof(int_vector)
class(int_vector)

booleans <- int_vector == 1
typeof(booleans)
class(booleans)

can you mix types in a vector?



In [ ]:

    
combine_char_num <- c(random_norms, some_letters)
typeof(combine_char_num)

Lists

to combine types, make list



In [ ]:

    
list_char_num <- list(nums = random_norms, chars = some_letters)
typeof(list_char_num)
lapply(list_char_num, typeof)

Matrices

matrices, same length, same type



In [ ]:

    
matrix_num <- matrix(rnorm(10), nrow = 5, ncol = 2)
# reuse
matrix_num_reuse <- matrix(rnorm(11), nrow = 6, ncol = 4)
matrix_mix <- matrix(c(rnorm(10), letters[1:10]), nrow = 10, ncol = 2)
typeof(matrix_mix)

data.frames

To mix elements in a rectangular object/table, use data.frames:



In [ ]:

    
df_char_num <- data.frame(chars = letters[1:10], nums = rnorm(10))
lapply(df_char_num, typeof)

## data.frames must have same length in each column
df_char_num <- data.frame(chars = letters[1:8], nums = rnorm(10))

Helpful Functions



In [ ]:

    
# see your workspace
ls()


# check working directory, change directory
getwd()
setwd(getwd())

# create a sequence of numbers
1:10
seq(1, 10)
seq(1, 10, 2)

# get help
?seq
help(seq)

# type tests

is.character(some_letters)
is.numeric(some_letters)
is.atomic(some_letters)
is.atomic(df_char_num)

# remove object from workspace
rm(some_letters)

# remove all visible objects

rm(list = ls())