List in R

Published by onesixx on 16-02-1116-02-11

http://www.r-tutor.com/r-introduction/list
http://dsmoon.tistory.com/entry/R언어4리스트

List 란?

다른 objects를 포함하는 generic vector

remove element of a List

LL <- list( "sixx", NULL, NULL, c(21,32,11), "bar")

[[1]]
[1] "sixx"

[[2]]
NULL

[[3]]
NULL

[[4]]
[1] 21 32 11

[[5]]
[1] "bar"

names(LL) <- seq_along(LL)

$`1`
[1] "sixx"

$`2`
NULL

$`3`
NULL

$`4`
[1] 21 32 11

$`5`
[1] "bar"

Remove by name

LL[["5"]] <- NULL

Remove by condition

LL[LL %in% "sixx"] <- NULL

Remove duplicated element

LL[duplicated(LL)]<-NULL

Remove NULL element

LL <- Filter(Negate(is.null), LL)
#or
LL[sapply(LL, print)] <- NULL
#or
LL[lengths(LL)!=0]

example2

https://statisticsglobe.com/remove-element-from-list-in-r

myList <- list(
            a = c(0, 8, 1, 9),                 
            b = 666,
            c = "sixx")

#1. assign NULL
myList[2] <- NULL
myList[c(2,3)] <- NULL
myList['c'] <- NULL

#2. minus sign
result <- myList[-2]
result <- myList[-c(2,3)]

#3. by Name 
result <- myList[names(myList) %in% "b"==FALSE]
result <- myList[names(myList) %in% c("b","c")==FALSE]

result <- myList[names(myList) !="b"]

col <- c('a','b')
for(i in col){
  i <- as.character(i)
  myList[i] <- NULL
}

List 생성및 Member Reference

Vector

pre  <- c(54, 64, 75)
post <- c(53, 60, 70, 60)
diet_named <- list(Before=pre, After=post)    

> diet_named
$Before
[1] 54 64 75

$After
[1] 53 60 70 60

> diet_named[[1]]
> diet_named$Before       # same 이름이 있는 경우에만 
[1] 54 64 75

diet_unnamed <- list(pre, post)
> diet_unnamed
[[1]]
[1] 54 64 75

[[2]]
[1] 53 60 70 60 

> diet_unnamed[[1]]
[1] 54 64 75
> diet_unnamed$Before       # 활용불가!! 
NULL

DataFrame

predd  <- data.table( height=c(54, 64, 75), weight=c(49, 52, 77))
postdd <- data.table( height=c(53, 60, 70), weight=c(49, 53, 70))
diet_DD <- list(Before=predd, After=postdd)

> predd         %>% class     # element is Data.Table
[1] "data.table" "data.frame"
> diet_DD[[1]]   %>% class
[1] "data.table" "data.frame"

unlist (Flatten Lists)

use.names = TRUE 인 경우, list명 + column명 + row 명 순

> diet_named %>% unlist()
Before1 Before2 Before3  After1  After2  After3  After4 
     54      64      75      53      60      70      60 

> diet_unnamed %>% unlist()
[1] 54 64 75 53 60 70 60

> diet_DD %>% unlist()                  # length 12인 numeric Vector
Before.height1 Before.height2 Before.height3 Before.weight1 Before.weight2 Before.weight3  After.height1  After.height2  After.height3  After.weight1 
            54             64             75             49             52             77             53             60             70             49 
 After.weight2  After.weight3 
            53             70

recursive=F 인 경우, Flatten가능한 부분까지 …
recursive=F 인 경우, 가장 상위 List만 Flatten 시킨다.

test <- list(Before=pre, After=postdd)

$Before
[1] 54 64 75

$After
   height weight
1:     53     49
2:     60     53
3:     70     70

> test %>% unlist()
> test %>% unlist(recursive=F)%>% unlist(recursive=F)   #same
      Before1       Before2       Before3 After.height1 After.height2 After.height3 After.weight1 After.weight2 After.weight3 
           54            64            75            53            60            70            49            53            70 

> test %>% unlist(recursive=F)
$Before1
[1] 54

$Before2
[1] 64

$Before3
[1] 75

$After.height
[1] 53 60 70

$After.weight
[1] 49 53 70

nested list

ui = fluidPage(
  selectizeInput("state", "Choose a state:", choices="", multiple=F),
  textOutput("result")
)
server = function(input, output, session) {
  # choiceList <- list( `2019-01-01` = list("2019-01-01-10.fst", "2019-01-01-2.fst", "2019-01-01-11.fst"),
  #                     `2019-02-01` = list("2019-02-01-12.fst", "2019-02-01-all.fst"),
  #                     `2019-03-01` = list("2019-03-01-3.fst",  "2019-03-01-20.fst", "2019-03-01-10.fst"))
  
  files <- c("2019-01-01-10.fst", "2019-01-01-2.fst", "2019-01-01-11.fst",
             "2019-02-01-12.fst", "2019-02-01-all.fst",
             "2019-03-01-3.fst",  "2019-03-01-20.fst", "2019-03-01-10.fst")
  groups <- str_sub(files, start=1, end=10) %>% unique()
  
  choiceList <- vector("list", length(groups))
  names(choiceList) <- groups
  for(i in seq_along(groups)){
    choiceList[[i]] <- files[str_detect(files, groups[i])] %>%
      str_replace_all(".fst","") %>% 
      str_split(" ")
  }
  updateSelectizeInput(session, inputId="state", choices=choiceList)
  
  output$result <- renderText({
    paste("You chose", input$state)
  })
}
shinyApp(ui, server)

vector vs. unvector(?)

> lc <- list(c("A","B","C"))

> lc
[[1]]
[1] "A" "B" "C"

----------------------------------------
lc <- c("A","B","C") %>% str_split(" ")
identical(l, lc)
----------------------------------------


> lc[[1]]
[1] "A" "B" "C"
> lc[[2]]
Error in lc[[2]] : subscript out of bounds


> lc[1]
[[1]]
[1] "A" "B" "C"

> lc[2]
[[1]]
NULL

> l  <- list("A","B","C")

> l
[[1]]
[1] "A"

[[2]]
[1] "B"

[[3]]
[1] "C"

> l[[1]]
[1] "A"
> l[[2]]
[1] "B"


> l[1]
[[1]]
[1] "A"

> l[2]
[[1]]
[1] "B"

Convert List to DT

#by row & column
do.call(cbind, myList))   %>% as.data.table()
do.call(cbind, myList))   %>% as.data.table()

List in R

http://www.r-tutor.com/r-introduction/list
http://dsmoon.tistory.com/entry/R언어4리스트

List 란?

remove element of a List

Remove by name

Remove by condition

Remove duplicated element

Remove NULL element

example2

https://statisticsglobe.com/remove-element-from-list-in-r

List 생성및 Member Reference

Vector

DataFrame

unlist (Flatten Lists)

nested list

vector vs. unvector(?)

Convert List to DT

onesixx

Reshaping

Simple Imputation (simputation)

Reshaping

seq()

Reshaping

group , cycle by rule

List in R

List 란?

remove element of a List

Remove by name

Remove by condition

Remove duplicated element

Remove NULL element

example2

List 생성및 Member Reference

Vector

DataFrame

unlist (Flatten Lists)

nested list

vector vs. unvector(?)

Convert List to DT

onesixx

Related Posts