The Tutor House Day 02 R Objects and Commands
R Objects and Commands
3 types of R objects, vector, data frame, and matrix.
By Montaque Reynolds
January 26, 2021
Vectors
Contains a set of values. These include vec_num
, number vector and vec_char
whwhich is a character vector. c()
combines the elements of a vector and <-
assigns a vector to a variable.
vec_num <- c(1, 5, 6, 3)
vec_num
## [1] 1 5 6 3
vec_char <- c("apple", "banana", "mandarin", "melon")
vec_char
## [1] "apple" "banana" "mandarin" "melon"
Once we have created a vector, we can extract its elements using the []
operator. For instance, you can extract the first element [1]
,
vec_char <- c("apple", "banana", "mandarin", "melon")
vec_char[1]
## [1] "apple"
or the first 3 elements [1:3]
.
vec_char[1:3]
## [1] "apple" "banana" "mandarin"
Some functions
Arithmetic, Multiplication, Division, Subtraction
vec_num2 <- vec_num + 2
vec_num3 <- vec_num / 2
vec_num4 <- vec_num * 4
vec_num5 <- vec_num - 1
vec_num
## [1] 1 5 6 3
# Addition
vec_num2
## [1] 3 7 8 5
# Division
vec_num3
## [1] 0.5 2.5 3.0 1.5
# Multiplication
vec_num4
## [1] 4 20 24 12
# Subtraction
vec_num5
## [1] 0 4 5 2
Comparing vectors using relational operators (returns TRUE
or FALSE
)
vec_logi_gt5 <- vec_num >= 5
vec_logi_gt5
## [1] FALSE TRUE TRUE FALSE
We can do this using the equality operator only on character vectors
vec_logi_apple <- vec_char == "apple"
vec_logi_apple
## [1] TRUE FALSE FALSE FALSE
We can also concatenate vector elements using paste()
.
vec_char2 <- paste(c("red", "yellow", "orange", "green"), vec_char)
print(vec_char2)
## [1] "red apple" "yellow banana" "orange mandarin" "green melon"
We can also set names to the elements of a numeric vector
names(vec_num) <- vec_char
print(vec_num)
## apple banana mandarin melon
## 1 5 6 3
Data Frames
Data Frames combine multiple vectors to construct a data set. However, though vectors can be of different types, they can only be combined if they have the same lengths.
dat_fruit <- data.frame(name = vec_char, count = vec_num)
print(dat_fruit)
## name count
## apple apple 1
## banana banana 5
## mandarin mandarin 6
## melon melon 3