重複一個功能並保存結果。 R

Question

有一些類似這個問題，但我仍然無法解決我的特殊問題。我有一個函數可以從df中獲取行的隨機樣本。使用dplyr庫。

rohis <- function(dat, ind, n) { 
    ind <- enquo(ind) 
    dat %>% 
     filter(UQ(ind) %in% sample(unique(UQ(ind)), n)) %>% 
     slice(sample(row_number())) 
} 

現在我想重複此功能的10倍，並將結果保存在一個列表：

lst <- list() 
for (i in 1:10){ 
    i = rohis(data, ind, 3) 
    lst[[length(lst) + 1]] = i 
} 

但是得到這個錯誤：

Error in lst[[length(lst) + 1]] <- i : 
object of type 'closure' is not subsettable 

這裏有一些數據：

data <- structure(list(pos1 = c(5, 15, 25, 40, 80, 5, 18, 22, 38, 84, 
        5, 16, 50, 92, 31, 50, 20, 30, 50, 70, 27, 50, 60, 50, 90, 20, 
        40, 54, 65, 78, 7, 17, 27, 42, 85, 10, 19, 25, 39, 88, 10, 19, 
        55, 93, 32, 54, 22, 35, 52, 72, 29, 55, 65, 55, 95, 22, 46, 57, 
        67, 79), pos2 = c(10, 17, 30, 42, 90, 10, 20, 24, 42, 87, 10, 
             19, 52, 100, 40, 70, 25, 32, 60, 90, 30, 60, 71, 60, 100, 25, 
             50, 50, 69, 90, 19, 27, 39, 49, 99, 20, 29, 30, 49, 92, 20, 29, 
             59, 100, 48, 76, 30, 39, 67, 98, 36, 68, 76, 65, 100, 30, 55, 
             55, 70, 100), chr = c(1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 1, 1, 1, 
                  1, 1, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 1, 1, 1, 1, 
                  1, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 
                  2, 2, 2, 2, 2), ind = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
                           1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 
                           3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
                           4L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 6L, 6L, 6L, 6L, 6L, 
                           6L, 6L, 6L, 6L, 6L), .Label = c("A", "B", "C", "D", "E", "F"), class ="factor")), .Names = c("pos1", "pos2", "chr", "ind"), row.names = c(NA, -60L), class = "data.frame") 

Answer 1

方案

如果要篩選特定ind，然後品嚐隨機行中，你可以試試這個功能

rohis <- function(dat, I, n) { 
    require(dplyr) 
    dat %>% 
     filter(ind %in% I) %>% 
     slice(sample(nrow(.), n)) 
} 

要重複10次，並保存在一個列表中做

library(purrr) 
ans <- map(1:10, ~rohis(data, "A", 3)) 

要過濾多個ind

ans <- map(1:10, ~rohis(data, c("A","E"), 3)) 

替代

要隨機抽樣行，而不過濾

alt <- function(dat, n) { 
    dat %>% 
     slice(sample(nrow(.), n)) 
} 

map(1:10, ~alt(data, 3)) 

抽樣隨機IND

alt2 <- function(dat, n) { 
    I <- sample(unique(dat$ind), n) 
    dat %>% 
     filter(ind %in% I) 
} 

map(1:10, ~alt2(data, 3))