如何处理lapply中的特定单元格? [英] How to address specific cell in lapply?

问题描述

我要升级"我的代码通过使用lapply函数替换使用for循环的mass-import.使用 lapply(list.files()，read.csv)后，我得到了一个数据帧列表.问题是，数据有点混乱，并且在一个特定的单元格中只提到了一些事情(例如参与者的性别).当我使用for循环时，这不是问题，因为我只能引用特定的单元格.当我使用时:

I want to "upgrade" my code by replacing mass-import using for loop with lapply function. After using lapply(list.files(), read.csv) I've got a list of dataframes. The problem is, the data is a bit messy and some things (like participant's sex) are mentioned only once, in one specific cell. It wasn't a problem when I used a for loop, as I could just refer to a specific cell. When I used:

for (x in list.files()) {
temp <- read.csv(x)
temp %>% slice(4:11) %>% select(form_2.index, form_2.response) %>% mutate(sex = temp[1,4])
#temp[1,4] is the one cell where the participant's sex is mentioned
database <- rbind(datadase, temp)

每个临时变量看起来像这样:

each temp variable looked like this:

  form_2.index form_2.response sex$form.response
         <dbl> <chr>           <chr>             
1            1 yes             male         
2            2 no              male         
3            3 no              male         
4            4 yes             male         
5            5 yes             male         
6            6 yes             male         
7            7 no              male         
8            8 no              male         

这就是我想要的.但是在使用lapply时如何引用某个单元格?以下代码不起作用，因为temp变量现在是一个列表:

That's what I want. But how can I refer to a certain cell when using lapply? The following code doesn't work, as the temp variable is now a list:

temp <- lapply(list.files(), read_csv())
temp %>% lapply(slice, 4:11) %>% lapply(select, form_2.index, form_2.response) %>% lapply(mutate, plec = temp[1,4])

slice 和 select 函数正常工作，问题出在 mutate 部分.给定一个列表，我需要指向列表中的某个元素，不仅是行和列，还应该怎么做?毕竟，我希望在每个元素中都能做到.有什么想法吗?

The slice and select functions work all right, the problem lies in the mutate part. Given it's a list, I need to point to a certain element of the list, not only column and row, but how can I do that? After all, I want it to be done in each element. Any ideas?

推荐答案

您可以:

library(dplyr)

temp <- lapply(list.files(), function(x) {
  tmp <- readr::read_csv(x)
  tmp %>%
    slice(4:11) %>% 
    select(form_2.index, form_2.response) %>% 
    mutate(sex = tmp[1,4])
})

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