如何动态访问数据框列表中的特定属性

Question

我有一个数据框列表。我正在尝试访问列表中每个数据框内的特定属性。可以使用以下代码提取特定属性DP.UniqueId。

> attr(new_data$A$AA, "SpotfireColumnMetaData")$DP.UniqueId
[1] "A-024"

这种方法的问题在于它不是动态的。此外，我拥有的大数据列表中有数千个数据框，对于每个数据框，我都想提取这个特定的DP.UniqueId 属性。

如果我必须应用 lapply() 或 for loop() 来动态获取此属性，那么我必须将其引用为：

> attr(new_data[1][1], "SpotfireColumnMetaData")$DP.UniqueId
NULL

但它看起来像在R，attr() 不能像上面的代码那样被引用。有没有办法动态提取特定属性并将其存储在数据框中？

数据

new_data <- list(A = structure(list(AA = structure(5.49485, SpotfireColumnMetaData = list(
  DP.TestNumber = "111", DP.Type = "", DP.TestName = "ABC", 
  DP.Info = "PTR", DP.TestUnit = "Mohm", DP.Statistic = "raw", 
  DP.Program = "", DP.ScaleFactor = 0L, DP.FilteredOutCells = 0L, 
  Limits.Prod.Lower = 2, Limits.Prod.Target = NaN, Limits.Prod.Upper = 7, 
  Limits.Spec.Lower = -Inf, Limits.Spec.Target = NaN, Limits.Spec.Upper = Inf, 
  Limits.Outlier.Lower = -Inf, Limits.Outlier.Target = NaN, 
  Limits.Outlier.Upper = Inf, Limits.Whatif.Lower = -Inf, Limits.Whatif.Target = NaN, 
  Limits.Whatif.Upper = Inf, DP.ParamType = "PARAMETRIC", DP.BlockId = "", 
  DP.Scratch = "", DP.ColumnId = "", Dp.BaseName = "", DP.FTR.testtxt = "", 
  DP.PTR.testtxt = "A  -1 <> B", DP.DTR.textdat = "", 
  DP.MPR.pinnum = "0", DP.UniqueId = "A-024"))), class = "data.frame", row.names = c(NA,-1L)),
  B = structure(list(BB = structure(0.08707662, SpotfireColumnMetaData = list(
  DP.TestNumber = "112", DP.Type = "", DP.TestName = "ABC", 
DP.Info = "PTR", DP.TestUnit = "Mohm", DP.Statistic = "raw", 
DP.Program = "", DP.ScaleFactor = 0L, DP.FilteredOutCells = 0L, 
Limits.Prod.Lower = 2, Limits.Prod.Target = NaN, Limits.Prod.Upper = 7, 
Limits.Spec.Lower = -Inf, Limits.Spec.Target = NaN, Limits.Spec.Upper = Inf, 
Limits.Outlier.Lower = -Inf, Limits.Outlier.Target = NaN, 
Limits.Outlier.Upper = Inf, Limits.Whatif.Lower = -Inf, Limits.Whatif.Target = NaN, 
Limits.Whatif.Upper = Inf, DP.ParamType = "PARAMETRIC", DP.BlockId = "", 
DP.Scratch = "", DP.ColumnId = "", Dp.BaseName = "", DP.FTR.testtxt = "", 
DP.PTR.testtxt = "A  -1 <> B", DP.DTR.textdat = "", 
DP.MPR.pinnum = "0", DP.UniqueId = "B-025"))), class = "data.frame", row.names = c(NA,-1L)))

Answer 1

您似乎可以使用purrr 包轻松完成此操作。例如

library(purrr)
new_data %>% map(pluck, 1, attr_getter("SpotfireColumnMetaData"), "DP.UniqueId")
# $A
# [1] "A-024"
# $B
# [1] "B-025"

map() 将遍历初始列表，然后pluck() 可以处理深度提取。