Cau chi co 1 dieu kien

x <- 2
if (x<0) {print("am")
} else {print("duong")
}

## [1] "duong"

Cau co tu 2 dieu kien tro len

if (condition1) else { print(“a111”)} else if (condition2) {print(“a2222”)} else {print(“a333”) }

x <- 4
if (x<0) {print("am")
} else if (x==0) {print("bang 0")
} else {print("so duong")
}

## [1] "so duong"

while loop

# Extend/adapt the while loop
speed <- 64
while (speed > 30) {
  print(paste("Your speed is", speed))
  if (speed > 48) {
    print("Slow down big time!")
    speed <- speed - 11
  } else {
    print("Slow down!")
    speed <- speed - 6
  }
}

## [1] "Your speed is 64"
## [1] "Slow down big time!"
## [1] "Your speed is 53"
## [1] "Slow down big time!"
## [1] "Your speed is 42"
## [1] "Slow down!"
## [1] "Your speed is 36"
## [1] "Slow down!"

For Loop

li <- c("ab",
       "b",
       "abc")
for (ch in li) {
  if (nchar(ch)>2) {
      next # next is skip ch co so ki tu nhieu hon 2
}
print(ch)
}

## [1] "ab"
## [1] "b"

them text vao sau cac char

for (i in 1:length(li)) {
  print(li[i])
}

## [1] "ab"
## [1] "b"
## [1] "abc"

for (i in 1:length(li)) {
  print(paste(li[i],"is position",
              i, "in vector li"))
}

## [1] "ab is position 1 in vector li"
## [1] "b is position 2 in vector li"
## [1] "abc is position 3 in vector li"

##Function

l <- c(2,4,NA)
sd(l,na.rm = T)# dung n.rm=T de remove NA. unless the result will display: NA

## [1] 1.414214