将深度嵌套的文件保存到具有特定文件名的特定目录中 [英] Saving deeply nested files to specific directories with specific filenames

问题描述

给出一个三级嵌套列表:

Given a 3 level nested list:

mylist <- list("1000"=list("cars"=list("fast"=mtcars[1:10,], "slow"=mtcars[11:15,]), "flower"=iris), "2000"=list("tooth"=ToothGrowth, "air"=airquality, "cars"=list("cruiser"=mtcars[5:12,], "fast"=mtcars[1:3,], "mild"=mtcars[9:18,]))) 

(即:mylist$1000$cars$fast，其中fast是数据帧，而cars和1000是mylist中的嵌套列表)

(ie: mylist$1000$cars$fast, where fast is a dataframe, and cars and 1000 are nested lists in mylist)

我想将每个最里面的数据帧(即:fast)另存为.csv，并以df名称作为文件名，例如:fast.csv，和文件保存在以第二级列表命名的目录中，即:~/1000/fast.csv.

I'd like to save each innermost dataframe, (ie: fast) as a .csv with the df name as it's file name, ie: fast.csv, and I want the file to be saved in a directory that is named after the second level of list, ie: ~/1000/fast.csv.

每个目录已经存在，因此不需要创建新的1000和2000目录.

Each directory already exists, so I do not need to create a new 1000 and 2000 directory.

我的直觉是做一个嵌套的lapply或lapply/mapply组合...但是要跟踪不同的级别及其名称对我构成了挑战.我知道purrr具有iwalk功能，但是我不确定如何在深度嵌套的列表中使用它.

My instinct is to do a nested lapply or lapply/mapply combination...but keeping track of the different levels and their names is challenging me. I know that purrr has the iwalk function, but I'm not sure how to use it within deeply nested list.

我当前的尝试失败.

lapply(mylist, function(d){
  lapply(names(mylist), function(id){
    lapply(names(d$cars), function(s){
    lapply(d$cars, function(a){
        write.csv(a, paste0(outdir, id, "/", s, ".csv"))})})})})

输出结果将单个文件以多种名称保存到所有目录中.即:~/1000/cruiser.csv，~/1000/fast.csv，~/1000/mild.csv，~/2000/cruiser.csv，~/2000/fast.csv，~/2000/mild.csv ...，其中所有文件实际上只是mylist$2000$cars$mild

The output results in a single file being saved under multiple names into all the directories. ie: ~/1000/cruiser.csv, ~/1000/fast.csv, ~/1000/mild.csv, ~/2000/cruiser.csv, ~/2000/fast.csv, ~/2000/mild.csv ... where all the files are actually just a csv of mylist$2000$cars$mild

推荐答案

假定子文件夹在工作目录中:

Assuming the sub-folders are within the working directory:

purrr::iwalk(mylist, function(el, folder){
  purrr::walk(el,
              function(sub_el, folder){
                if(class(sub_el) == "list"){
                  purrr::iwalk(sub_el,
                               function(dat, dat_name, folder){
                                 write.csv(dat,
                                           # below line specifies file path of new file
                                           paste0(folder, "/", dat_name, ".csv"))
                               },
                               folder = folder)
                }
              },
              folder = folder)
})

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