R-将空类型的列表转换为数据帧

我有以下清单：

test <- list(author = list(name = "Yihui Xie", email = "BLINDED", 
    date = "2021-04-14T15:26:29Z"), committer = list(name = "Yihui Xie", 
    email = "xie@yihui.name", date = "2021-04-14T15:27:13Z"), 
    message = "start the next version", tree = list(sha = "f4032fb23c2e3c6005a76f4e117f6489d321c721", 
        url = "https://api.github.com/repos/rstudio/blogdown/git/trees/f4032fb23c2e3c6005a76f4e117f6489d321c721"), 
    url = "https://api.github.com/repos/rstudio/blogdown/git/commits/5aeb809c68cfa1a9e616bc9ed9878c3ea5d05300", 
    comment_count = 0L, verification = list(verified = FALSE, 
        reason = "unsigned", signature = NULL, payload = NULL))

预期输出：

下面是我能够正确转换的另一个列表。正如您所看到的，这一个没有缺少的值，但我在这里添加它，以便您可以看到我需要什么（这是转换的dput）：

结构（列表（author.name=structure（1L，.Label=“Christophe Dervieux”，class=“factor”）， author.email=结构（1L，.Label=“盲”，class=“factor”）， author.date=结构（1L，.Label=“2021-05-26T16:19:44Z”，class=“factor”）， committer.name=结构（1L，.Label=“GitHub”，class=“factor”）， committer.email=结构（1L，.Label=”noreply@github.com“，class=“factor”）， 提交人日期=结构（1L，.Label=“2021-05-26T16:19:44Z”，class=“factor”）， message=structure（1L，.Label=“clean_duplicates（）现在知道blogdown呈现方法（#629）”，class=“factor”）， tree.sha=结构（1L，.Label=“f1d056b93ce0d06051d5fd6b9e9df2d934059f6”，class=“factor”）， tree.url=结构（1L，.Label=”https://api.github.com/repos/rstudio/blogdown/git/trees/f1d056b93ce0d060501d5fd6b9e9df2d934059f6“，class=“factor”）， url=结构（1L，.Label=”https://api.github.com/repos/rstudio/blogdown/git/commits/00a20903f0b2953f8f350d69bffdcd9c50cda5b1“，class=“factor”）， 注释计数=0L，verification.verified=TRUE，verification.reason=structure（1L，.Label=“valid”，class=“factor”）， verification.signature=结构（1L，.标签="-----2）美国，纽约市，纽约市，纽约市，纽约市，纽约市，纽约市，纽约市，纽约市，纽约市，纽约市，纽约市，纽约市，纽约市，vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvB/WX8sE2BLsU6zPg\nePZMyTfLulDXdhoMK6vU6Lj5faiWbLk/xE9zaBKGiRqKALtBsR75YnTal5Gb/qM=\n=bVRa\n------结束PGP签名------\n“，class=“factor”）， verification.payload=structure（1L，.Label=“tree f1d056b93ce0d060501d5fd6b9e9df2d934059f6\nPart 20A58B39F5CBDA7911C8C0CDB35A4BB31AA52\nauthor Christophe Dervieux 1622045984+0200\ncommitter GitHub 1622045984+0200\n\n\nclean\n重复项（）现在知道blogdown呈现方法（#629）\n\n\n“，class=“factor”）、class=“data.frame，row.names=c（NA， -1L）

---

我们可以递归地将

NULL

值替换为

NA

，然后将

flatten

ed数据更改为

data.frame

library(rrapply)
library(dplyr)
out2 <- rrapply(test, f = function(x) replace(x, is.null(x), NA), 
        how = 'flatten') %>%
     as.data.frame.list %>%
     type.convert(as.is = TRUE)

structure(list(author.name = structure(1L, .Label = "Christophe Dervieux", class = "factor"), 
    author.email = structure(1L, .Label = "BLINDED", class = "factor"), 
    author.date = structure(1L, .Label = "2021-05-26T16:19:44Z", class = "factor"), 
    committer.name = structure(1L, .Label = "GitHub", class = "factor"), 
    committer.email = structure(1L, .Label = "noreply@github.com", class = "factor"), 
    committer.date = structure(1L, .Label = "2021-05-26T16:19:44Z", class = "factor"), 
    message = structure(1L, .Label = "clean_duplicates() is now aware of blogdown rendering method (#629)", class = "factor"), 
    tree.sha = structure(1L, .Label = "f1d056b93ce0d060501d5fd6b9e9df2d934059f6", class = "factor"), 
    tree.url = structure(1L, .Label = "https://api.github.com/repos/rstudio/blogdown/git/trees/f1d056b93ce0d060501d5fd6b9e9df2d934059f6", class = "factor"), 
    url = structure(1L, .Label = "https://api.github.com/repos/rstudio/blogdown/git/commits/00a20903f0b2953f8f350d69bffdcd9c50cda5b1", class = "factor"), 
    comment_count = 0L, verification.verified = TRUE, verification.reason = structure(1L, .Label = "valid", class = "factor"), 
    verification.signature = structure(1L, .Label = "-----BEGIN PGP SIGNATURE-----\n\nwsBcBAABCAAQBQJgrnUgCRBK7hj4Ov3rIwAAJNMIAD1/pWaW/NYsefSLx5tvcTyl\nfG+Nst5dxAYz1jvZBsiy/zGsrk42EneA391svg6SkW8brf37tNUq3Ob1fXxrknCB\nDctR6X1v281KS9ziFOXMC67HKeqSqWqFD/QaQ3Q2+TDUSdV2Gos6TN6asaBfcwku\nwadow9ZOnzi6tvT7KqWeFD05M8cHnPpTrbPJ8BUjkuf5mQog0xJY40Sev9DFg33P\nux6jhBKJZeN72UxK1K9zs/OvHOLerHoq/pt+mxFnmsf/Kgps2/WX8sE2BLsU6zPg\nePZMyTfLulDXdhoMK6vU6Lj5faiWbLk/xE9zaBKGiRqKALtBsR75YnTal5Gb/qM=\n=bVRa\n-----END PGP SIGNATURE-----\n", class = "factor"), 
    verification.payload = structure(1L, .Label = "tree f1d056b93ce0d060501d5fd6b9e9df2d934059f6\nparent 20a8258b39f5cbda7911cc8c0cdb35a4bb31aa52\nauthor Christophe Dervieux <cderv@rstudio.com> 1622045984 +0200\ncommitter GitHub <noreply@github.com> 1622045984 +0200\n\nclean_duplicates() is now aware of blogdown rendering method (#629)\n\n", class = "factor")), class = "data.frame", row.names = c(NA, 
-1L))

library(rrapply)
library(dplyr)
out2 <- rrapply(test, f = function(x) replace(x, is.null(x), NA), 
        how = 'flatten') %>%
     as.data.frame.list %>%
     type.convert(as.is = TRUE)

dim(out2)
#[1]  1 15