r - 使用 purrr 取消嵌套列表并收集项目

Question

我有一个列表，如:

list(list(goals = c(42L, 52L, 55L), 
          season = "88", 
          player = c("a", "b","c")), 
     list(goals = c(41L,53L, 37L, 40L), 
          season = "89", 
          player = c("a","b", "c", "d")))

我想将其转换为长格式的数据帧，例如:

goals player season 
42    a      88
52    b      88
.
.
41    a      89
53    b      89
.

我可以使用 plyr 来实现这一点喜欢: plyr::ldply(mylist, data.frame, .id="season"
我想可能有一种更新的方法可以使用 purrr或 dplyr ?

Answer 1

我们可以通过转换 list 来做到这一点。元素到 tibble通过循环遍历 list使用 map

library(tidyverse)
lst1 %>%
    map_df(as_tibble)
# A tibble: 7 x 3
#  goals player season
#  <dbl> <chr>   <dbl>
#1    42 a          88
#2    52 b          88
#3    55 c          88
#4    41 a          89
#5    53 b          89
#6    37 c          89
#7    48 d          89

一个 base R选项是转换为 list的 data.frame s 然后 rbind

do.call(rbind, lapply(lst1, as.data.frame))

数据

lst1 <- list(list(goals = c(42, 52, 55), player = c("a", "b", "c"), season = 88), 
     list(goals = c(41, 53, 37, 48), player = c("a", "b", "c", 
     "d"), season = 89))