myscript.R

4+3
5*4
8+2*10
(8+2)*10

x=7
x+6
x * 8
x<-34
x
assign("a",23)
a
a+5
rm("a")
a

# checking types
a=12
b="himanshu"
class(a)
class(b)

is.numeric(a)
is.numeric(b)

#assigning date
a = as.Date("18-06-2019")
class(a)
b = "18-06-2019"
class(b)

#checking length
nchar(a)
nchar("a")

8!=4
8<4
8>4
8>8
8>=8
8<=8
"himanshu"=="bvp"
"himanshu"=="himanshu"
"himanshu"!="himanshu"

# if implementation
x <- c("what","is","truth")
if("Truth" %in% x) {
  print("Truth is found the first time")
} else if ("truth" %in% x) {
  print("truth is found the second time")
} else {
  print("No truth found")
}

x <- switch(
  3,
  "first",
  "second",
  "third",
  "fourth"
)
print(x)

a1 =c(1,2,3,4,5,6)
a1^2
sqrt(a1)
a1 = 1:19
a1
length(a1)


m1 = 1:10
m2 = 31:40
m1
m2
m1+m2
m1*m2
# LOOPS
v <- c("Hello","loop")
cnt <- 2

repeat {
  print(v)
  cnt <- cnt+1
  
  if(cnt > 5) {
    break
  }
}

v <- c("Hello","while loop")
cnt <- 2

while (cnt < 7) {
  print(v)
  cnt = cnt + 1
}

v <- LETTERS[1:4]
for ( i in v) {
  print(i)
}

v <- c("Hello","loop")
cnt <- 2

repeat {
  print(v)
  cnt <- cnt + 1
  
  if(cnt > 5) {
    break
  }
}

v <- LETTERS[1:6]
for ( i in v) {
  
  if (i == "D") {
    next
  }
  print(i)
}


# Create a sequence of numbers from 32 to 44.
print(seq(32,44))

# Find mean of numbers from 25 to 82.
print(mean(25:82))

# Find sum of numbers frm 41 to 68.
print(sum(41:68))


# Create a function to print squares of numbers in sequence.
new.function <- function(a) {
  for(i in 1:a) {
    b <- i^2
    print(b)
  }
}
# Call the function new.function supplying 6 as an argument.
new.function(6)

# Create a function without an argument.
new.function <- function() {
  for(i in 1:5) {
    print(i^2)
  }
}	

# Call the function without supplying an argument.
new.function()

# Create a function with arguments.
new.function <- function(a,b,c) {
  result <- a * b + c
  print(result)
}

# Call the function by position of arguments.
new.function(5,3,11)

# Call the function by names of the arguments.
new.function(a = 11, b = 5, c = 3)

# Create a function with arguments.
new.function <- function(a = 3, b = 6) {
  result <- a * b
  print(result)
}

# Call the function without giving any argument.
new.function()

# Call the function with giving new values of the argument.
new.function(9,5)

# Create a function with arguments.
new.function <- function(a, b) {
  print(a^2)
  print(a)
  print(b)
}

# Evaluate the function without supplying one of the arguments.
new.function(6)

# Strings
a <- 'Start and end with single quote'
print(a)

b <- "Start and end with double quotes"
print(b)

c <- "single quote ' in between double quotes"
print(c)

d <- 'Double quotes " in between single quote'
print(d)

e <- 'Mixed quotes" 
print(e)


a <- "Hello"
b <- 'How'
c <- "are you? "

print(paste(a,b,c))

print(paste(a,b,c, sep = "-"))

print(paste(a,b,c, sep = "", collapse = ""))


# Total number of digits displayed. Last digit rounded off.
result <- format(23.123456789, digits = 9)
print(result)

# Display numbers in scientific notation.
result <- format(c(6, 13.14521), scientific = TRUE)
print(result)

# The minimum number of digits to the right of the decimal point.
result <- format(23.47, nsmall = 5)
print(result)

# Format treats everything as a string.
result <- format(6)
print(result)

# Numbers are padded with blank in the beginning for width.
result <- format(13.7, width = 6)
print(result)

# Left justify strings.
result <- format("Hello", width = 8, justify = "l")
print(result)

# Justfy string with center.
result <- format("Hello", width = 8, justify = "c")
print(result)

# Changing to Upper case.
result <- toupper("Changing To Upper")
print(result)

# Changing to lower case.
result <- tolower("Changing To Lower")
print(result)

# Extract characters from 5th to 7th position.
result <- substring("Extract", 5, 7)
print(result)


###### VECTORS
# Atomic vector of type character.
print("abc")

# Atomic vector of type double.
print(12.5)

# Atomic vector of type integer.
print(63L)

# Atomic vector of type logical.
print(TRUE)

# Atomic vector of type complex.
print(2+3i)

# Atomic vector of type raw.
print(charToRaw('hello'))

# Creating a sequence from 5 to 13.
v <- 5:13
print(v)

# Creating a sequence from 6.6 to 12.6.
v <- 6.6:12.6
print(v)

# If the final element specified does not belong to the sequence then 
#it is discarded.
v <- 3.8:11.4
print(v)

# Create vector with elements from 5 to 9 incrementing by 0.4.
print(seq(5, 9, by = 0.4))


# The logical and numeric values are converted to characters.
s <- c('apple','red',5,TRUE)
print(s)


# Accessing vector elements using position.
t <- c("Sun","Mon","Tue","Wed","Thurs","Fri","Sat")
u <- t[c(2,3,6)]
print(u)

# Accessing vector elements using logical indexing.
v <- t[c(TRUE,FALSE,FALSE,FALSE,FALSE,TRUE,FALSE)]
print(v)

# Accessing vector elements using negative indexing.
x <- t[c(-2,-5)]
print(x)
print(t)

# Accessing vector elements using 0/1 indexing.
y <- t[c(1,0,0,0,0,0,1)]
print(y)

# Create two vectors.
v1 <- c(3,8,4,5,0,11)
v2 <- c(4,11,0,8,1,2)

# Vector addition.
add.result <- v1+v2
print(add.result)

# Vector subtraction.
sub.result <- v1-v2
print(sub.result)

# Vector multiplication.
multi.result <- v1*v2
print(multi.result)

# Vector division.
divi.result <- v1/v2
print(divi.result)


v1 <- c(3,8,4,5,0,11)
v2 <- c(4,11)
# V2 becomes c(4,11,4,11,4,11)

add.result <- v1+v2
print(add.result)

sub.result <- v1-v2
print(sub.result)

v <- c(3,8,4,5,0,11, -9, 304)

# Sort the elements of the vector.
sort.result <- sort(v)
print(sort.result)

# Sort the elements in the reverse order.
revsort.result <- sort(v, decreasing = TRUE)
print(revsort.result)

# Sorting character vectors.
v <- c("Red","Blue","yellow","violet")
sort.result <- sort(v)
print(sort.result)

# Sorting character vectors in reverse order.
revsort.result <- sort(v, decreasing = TRUE)
print(revsort.result)