R 기초; 리스트 인덱싱-1

R 기초; 리스트 인덱싱-1

product <- list("A002", "Mouse", 30000)
product
[[1]]
[1] "A002"

[[2]]
[1] "Mouse"

[[3]]
[1] 30000

product[[3]]
[1] 30000

product[[2]]
[1] "Mouse"

product[3]
[[1]]
[1] 30000

product[2]
[[1]]
[1] "Mouse"

class(product[[3]])
[1] "numeric"

class(product[3])
[1] "list"

product[3] * 0.9
Error in product[3] * 0.9 : 이항연산자에 수치가 아닌 인수입니다

product[[3]] * 0.9
[1] 27000

product[c(1, 2)]
[[1]]
[1] "A002"

[[2]]
[1] "Mouse"


product[c(FALSE, TRUE, TRUE)]
[[1]]
[1] "Mouse"

[[2]]
[1] 30000


product[-1]
[[1]]
[1] "Mouse"

[[2]]
[1] 30000


product <- list(id="A002", name="Mouse", price=30000)
product
$id
[1] "A002"

$name
[1] "Mouse"

$price
[1] 30000

product[["name"]]
[1] "Mouse"

product$name
[1] "Mouse"

product[c("name", "price")]
$name
[1] "Mouse"

$price
[1] 30000

product$fourth
NULL

product[[4]]
Error in product[[4]] : 첨자의 허용 범위를 벗어났습니다


product[c(4, 2, 5)]
$<NA>
NULL

$name
[1] "Mouse"

$<NA>
NULL


product[c("fourth", "name", "fifth")]
$<NA>
NULL

$name
[1] "Mouse"

$<NA>
NULL

lst <- list(one=1, two=2, three=list(alpha=3.1, beta=3.3))
lst
$one
[1] 1

$two
[1] 2

$three
$three$alpha
[1] 3.1

$three$beta
[1] 3.3


lst[["three"]]
$alpha
[1] 3.1

$beta
[1] 3.3


list[["three"]][["beta"]]
[1] 3.3

lst$three$beta
[1] 3.3