R 기초; 논리흐름 제어

R 기초; 논리흐름 제어

 

x <- pi

y <- 3

if (x > y) x

[1] 3.141593

if (x < y) x

 

if (x < y) x else y

[1] 3

 

x <- pi

y < 1:5

if (x < y) x else y

[1] FALSE FALSE FALSE TRUE TRUE

 

test <- c(TRUE, FALSE, TRUE, TRUE, FALSE)

yes <- 1:5

no <- 0

ifelse(test, yes, no)

[1] 1 0 3 4 0

 

ifelse(x > y, x, y)

[1] 3.141593 3.141593 3.141593 4.000000 5.000000

 

center <- function(x, type) {

  switch(type,

           mean = mean(x), 

           median = median(x),

           trimmed = mean(x, trim=0.1)

  )

}

 

x <- c(2, 3, 5, 7, 11, 13, 17, 19, 23, 29)

center(x, "mean")

center(x, "median")

center(x, "trimmed")

 

center <- function(x, type) {

  switch(type,

           mean = mean(x),

           median = median(x),

           trimmed = mean(x, trim=0.1),

           "Choose one of mean, median, and trimmed"

  )

}

 

center(x, "other")

 

repeat print("hello")

i <- 5

repeat {if(i > 25) break

  else {

    print(i)

    i <- 1+5

  }

}

[1] 5

[1] 10

[1] 15

[1] 20

[1] 25

 

# while loop

i <- 5

while (i <= 25) {

  print(i)

  i <- i + 5

}

[1] 5

[1] 10

[1] 15

[1] 20

[1] 25

 

# for loop

x <- c(2, 5, 3, 9, 8, 11, 6)

count <- 0

for (val in x) {

  if (val %% 2 == 0)  count = count + 1

}

print(count)

[1] 3

 

 

# For Loop Statement Example # 01

fruit <- c('Apple', 'Orange', 'Passion fruit', 'Banana')

for (i in fruit) {

  print(i)

}

[1] "Apple"

[1] "Orange"

[1] "Passion fruit"

[1] "Banana"

 

 

# For Loop Statement Example # 02

list <- c()

for (i in seq(1, 4, by=1)) {

  list[[i]] <- i*i

}

print(list)

[1] 1 4 9 16