Activity 3

#Creating vectors

subject_name <- c("John Doe", "Jane Doe", "Steve Graves")
temperature <- c(98.1, 98.6, 101.4)
flu_status <- c(FALSE, FALSE, TRUE)

#accesing to the third element

temperature [3]

[1] 101.4

#Including range between 1 to 2

temperature [1:2]

[1] 98.1 98.6

exclude item 1 and 2 using the minus sign

temperature[-1:-2]

[1] 101.4

use a vector to indicate whether to include item

temperature[c(TRUE, FALSE, TRUE)]

[1]  98.1 101.4

add gender factor

gender <- factor(c("MALE", "FEMALE", "MALE"))
gender

[1] MALE   FEMALE MALE  
Levels: FEMALE MALE

add blood type factor

blood <- factor(c("O", "AB", "A"),
                levels = c("A", "B", "AB", "O"))
blood

[1] O  AB A 
Levels: A B AB O

symptoms <- factor(c("SEVERE", "MILD", "MODERATE"),
                   levels = c("MILD", "MODERATE", "SEVERE"),
                   ordered = TRUE)
symptoms

[1] SEVERE   MILD     MODERATE
Levels: MILD < MODERATE < SEVERE

check for symptoms greater than moderate

symptoms > "MODERATE"

[1]  TRUE FALSE FALSE

#display information for a patient

subject_name[3]

[1] "Steve Graves"

temperature[1]

[1] 98.1

flu_status[2]

[1] FALSE

gender[3]

[1] MALE
Levels: FEMALE MALE

blood[2]

[1] AB
Levels: A B AB O

symptoms[2]

[1] MILD
Levels: MILD < MODERATE < SEVERE

subject1 <- list(fullname = subject_name[1], 
                 temperature = temperature[1],
                 flu_status = flu_status[1],
                 gender = gender[1],
                 blood = blood[1],
                 symptoms = symptoms[1])

subject1

$fullname
[1] "John Doe"

$temperature
[1] 98.1

$flu_status
[1] FALSE

$gender
[1] MALE
Levels: FEMALE MALE

$blood
[1] O
Levels: A B AB O

$symptoms
[1] SEVERE
Levels: MILD < MODERATE < SEVERE

subject1[3]

$flu_status
[1] FALSE

subject1[[2]]

[1] 98.1

subject1$temperature

[1] 98.1

subject1[c("temperature", "flu_status")]

$temperature
[1] 98.1

$flu_status
[1] FALSE

subject1[2:3]

$temperature
[1] 98.1

$flu_status
[1] FALSE

pt_data <- data.frame(subject_name, temperature, flu_status, gender,
                      blood, symptoms, stringsAsFactors = FALSE)

pt_data

pt_data$subject_name

[1] "John Doe"     "Jane Doe"     "Steve Graves"

pt_data[c("temperature", "flu_status")]

pt_data[1:3]

pt_data[2, 3]

[1] FALSE

pt_data[c(1, 3), c(2, 4)]

pt_data[, 1]

[1] "John Doe"     "Jane Doe"     "Steve Graves"

pt_data[1, ]

#Leave a row or column blank to extract all rows or columns

pt_data[ , ]

pt_data[c(1, 3), c("temperature", "gender")]

pt_data[-2, c(-1, -3, -5, -6)]

pt_data$temp_c <- (pt_data$temperature - 32) * (5 / 9)

pt_data[c("temperature", "temp_c")]

#Matrixes

m <- matrix(c(1, 2, 3, 4), nrow = 2)
m

     [,1] [,2]
[1,]    1    3
[2,]    2    4

m <- matrix(c(1, 2, 3, 4), ncol = 2)
m

     [,1] [,2]
[1,]    1    3
[2,]    2    4

m <- matrix(c(1, 2, 3, 4, 5, 6), nrow = 2)
m

     [,1] [,2] [,3]
[1,]    1    3    5
[2,]    2    4    6

m <- matrix(c(1, 2, 3, 4, 5, 6), ncol = 2)
m

     [,1] [,2]
[1,]    1    4
[2,]    2    5
[3,]    3    6

m[1, 1]

[1] 1

m[3, 2]

[1] 6

m[1, ]

[1] 1 4

m[, 1]

[1] 1 2 3