相关疑难解决方法(0)

我有一个这样的列表:

    x = list(a = 1:4, b = 3:10, c = NULL)
    x
    #$a
    #[1] 1 2 3 4
    #
    #$b
    #[1]  3  4  5  6  7  8  9 10
    #
    #$c
    #NULL

我想提取所有非null的元素.如何才能做到这一点？谢谢.

给定一个包含多个元素的列表，目标是将它们放入数据框中。这map_df对于常规列表非常有用，但对于不规则列表会给出错误。

例如，按照本教程进行以下操作：

library(purrr)\nlibrary(repurrrsive) # The data comes from this package\n\n\nmap_dfr(got_chars, magrittr::extract, c("name", "culture", "gender", "id", "born", "alive"))\n\n A tibble: 30 x 6\n   name               culture  gender    id born                                   alive\n   <chr>              <chr>    <chr>  <int> <chr>                                  <lgl>\n 1 Theon Greyjoy      Ironborn Male    1022 In 278 AC or 279 AC, at Pyke           TRUE \n 2 Tyrion Lannister   ""       Male    1052 In 273 AC, at Casterly Rock            TRUE \n 3 Victarion Greyjoy  Ironborn Male    1074 In 268 AC or …