r-programming-101.R

# vectors
vector <- c(10,20,30, "hello")

# lists 
list <- list(1, "hello", 0.5, list(1,2,3), c(2,3,4))

# data types
# logical
class(FALSE)
# numeric
class(10.5)
# integetr
class(10L)
# complex
class(2+3i)



# dataframe
patientID <- c(1, 2, 3, 4)
age <- c(25, 34, 28, 52)
diabetes <- c("Type1", "Type2", "Type1", "Type1")
status <- c("Poor", "Improved", "Excellent", "Poor")

patientdata <- data.frame(patientID, age, diabetes, status)

# exploring your dataset
str(patientdata)
str(titanic)
min(na.omit(titanic$Age))

# subsetting vector
vector1 <- c(5,6,3,4)
vector1[c(1,2)]
vector1[c(TRUE, TRUE, FALSE, TRUE)]
vector1 < 4.5
vector1[vector1 < 4.5]
vector2 <- c(first=1, second=2, etc=3)
vector2["etc"]

# subsetting lists
list[[1]]
class(list[[4]])

# subsetting matrices
a <- matrix(1:9, nrow=3)
a[2,3] # 8
a[2:3,2:3]
a[2:3,c(1,3)]

# data frames 
print(titanic)
titanic$Name
titanic['Name']
titanic[3,3]
titanic[3:9,3]
all_columns <- titanic[3:9,]
View(all_columns)

all_rows <- titanic[,c(2,3)]
View(all_rows)

subset <- titanic[3:9,c(3,5)]
View(subset)

# functions 
product = function(a,b) {
  return(a*b)
}
product(3,6)

# anonymous function & lapply
titanic$Age <- lapply(titanic$Age, function(x) x*2)

# loops
names = c("mary", "joseh", "jesus")
for (name in names) {
  print(name)
}

count = 0
while (count < 5){
  count = count + 1 
  print(count)
}