---

title: “R Data Structures”

# create vectors of data for three medical patients
presidents_name <- c("Lindon Johnson", "George Bush", "John Kennedy")
president_salary <- c(200000, 400000, 175000)
application_status <- c(FALSE, FALSE, TRUE)

presidents_name[2]

## [1] "George Bush"

president_salary[2:3]

## [1] 400000 175000

government_expenditure <- factor(c("LOW", "MODERATE", "HIGH"),
                                  levels = c("LOW", "MODERATE", "HIGH"),
                                  ordered = TRUE)

government_expenditure >"MODERATE"

## [1] FALSE FALSE  TRUE

presidents_name[1]

## [1] "Lindon Johnson"

president_salary[1]

## [1] 2e+05

application_status[1]

## [1] FALSE

government_expenditure[1]

## [1] LOW
## Levels: LOW < MODERATE < HIGH

#creating list for president
president_term <- list(fullname = presidents_name[1], 
                 salary = president_salary[1],
                 application_status = application_status[1],
                 government_expenditure = government_expenditure[1])

president_term

## $fullname
## [1] "Lindon Johnson"
## 
## $salary
## [1] 2e+05
## 
## $application_status
## [1] FALSE
## 
## $government_expenditure
## [1] LOW
## Levels: LOW < MODERATE < HIGH

presidency_data <- data.frame(presidents_name, president_salary, application_status,
                              government_expenditure, stringsAsFactors = FALSE)

presidency_data

##   presidents_name president_salary application_status government_expenditure
## 1  Lindon Johnson           200000              FALSE                    LOW
## 2     George Bush           400000              FALSE               MODERATE
## 3    John Kennedy           175000               TRUE                   HIGH

presidency_data$presidents_name

## [1] "Lindon Johnson" "George Bush"    "John Kennedy"

presidency_data[c("presidents_name", "government_expenditure")]

##   presidents_name government_expenditure
## 1  Lindon Johnson                    LOW
## 2     George Bush               MODERATE
## 3    John Kennedy                   HIGH

presidency_data[2:3]

##   president_salary application_status
## 1           200000              FALSE
## 2           400000              FALSE
## 3           175000               TRUE

presidency_data[2,2]

## [1] 4e+05

presidency_data[c(2,1),c(3,1)]

##   application_status presidents_name
## 2              FALSE     George Bush
## 1              FALSE  Lindon Johnson

m1 <- matrix(c(1, 2, 3, 4), nrow = 2)
m1

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

m2<-matrix(c(1,2,3,4),ncol = 2)
m2

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

m1[1,1]

## [1] 1

m2[2,1]

## [1] 2

m3 <- matrix(c(1, 2, 3, 4, 5, 6), nrow = 2)
m3

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

m4<-matrix(c(2,3,7,9,11,10),ncol = 2)
m4

##      [,1] [,2]
## [1,]    2    9
## [2,]    3   11
## [3,]    7   10

m4[1,]

## [1] 2 9

m4[,2]

## [1]  9 11 10