將 function 應用於數據幀的行返回數據幀列表

Question

我正在閱讀多個 Excel 工作簿，這些工作簿具有不同的閱讀范圍，並且可能存在於每個工作簿內的不同工作表中。 我正在使用一個主文件，其中包含文件名、我要調用數據的名稱、要讀取的范圍和工作表（如果不是工作表 1）。 這是我的主文件：

Files = structure(list(file = c("Alaska.xls", "Analysis of Y-chromosome STRs in Chile.xlsx", 
"Bolivia.xlsx", "carribean.xlsx", "Chachapoya.xlsx", "Colombian.XLSX", 
"ndigenous Maya population from Guatemala.xlsx", "Nicaragua Nunez.xls", 
"Nicaragua.xls", "Palha Brazil.xls", "Patagonia.xls", "Promega Y23 Haplotypes Jun2019.xlsx", 
"Roewer et al.XLS", "Rio de Janeiro.xls", "The geographic mosaic of Ecuadorian.xlsx", 
"Xu2015Data-original.xlsx"), name = c("Alaska", "Chile", "Bolivia", 
"Carribean", "Chachapoya", "Colombian", "Guatemala", "Nicaragua", 
"Nicaragua", "Palha", "Patagonia", "Promega", "Roewer", "Rio", 
"Ecuador", "Xu"), range = c("G3:X31", "E3:U981", "I4:X230", "C4:S611", 
"C2:Y185", "I3:Q80", "D1:S101", "B1:R165", "AQ2:BF167", "G2:AB2534", 
"B8:J108", "C2:AT226", "J1:Y1012", "B3:Q608", "G4:AB419", "C2:S981"
), sheet = c("Table S8 Y chromosome STRs", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", "")), class = "data.frame", row.names = c(NA, 
-16L))

它看起來像這樣：

> Files
                                            file       name     range                      sheet
1                                     Alaska.xls     Alaska    G3:X31 Table S8 Y chromosome STRs
2    Analysis of Y-chromosome STRs in Chile.xlsx      Chile   E3:U981                           
3                                   Bolivia.xlsx    Bolivia   I4:X230                           
4                                 carribean.xlsx  Carribean   C4:S611                           
5                                Chachapoya.xlsx Chachapoya   C2:Y185                           
6                                 Colombian.XLSX  Colombian    I3:Q80                           
7  ndigenous Maya population from Guatemala.xlsx  Guatemala   D1:S101                           
8                            Nicaragua Nunez.xls  Nicaragua   B1:R165                           
9                                  Nicaragua.xls  Nicaragua AQ2:BF167                           
10                              Palha Brazil.xls      Palha G2:AB2534                           
11                                 Patagonia.xls  Patagonia   B8:J108                           
12           Promega Y23 Haplotypes Jun2019.xlsx    Promega  C2:AT226                           
13                              Roewer et al.XLS     Roewer  J1:Y1012                           
14                            Rio de Janeiro.xls        Rio   B3:Q608                           
15      The geographic mosaic of Ecuadorian.xlsx    Ecuador  G4:AB419                           
16                      Xu2015Data-original.xlsx         Xu   C2:S981        

我想遍歷此數據框的每一行，並使用read_excel讀取文件，並將返回的數據框存儲在名稱設置為name的列表中。

我嘗試使用丑陋且不起作用的僅apply ：

readFiles = function(){
  Files = read.csv(system.file("extdata", "files.csv", package = "purps"))

  Sheets = vector(mode = "list", length = length(Files$File))
  names(Sheets) = Files$Name

  readFile = function(row){
    row = as.list(row)
    path = system.file("extdata", file, package = "purps")
    read_excel(path, range = row$range, sheet = ifelse(row$sheet == "", NULL, row$sheet))
  }

  Sheets = apply(Files, 1, readFile)

  return(Sheets)
}

> readFiles()
 Error in file.path(packagePath, ...) : 
  cannot coerce type 'closure' to vector of type 'character' 

我確信有一個優雅的解決方案使用purrr或其他我不知道的東西，我也確信我可以通過循環來做到這一點。 但必須有一種更緊湊的方式。

Answer 1

您可以嘗試將Files中的每一行拆分為數據幀列表，然后將其傳遞給readFiles function。

readFiles = function(row){
   path = system.file("extdata", file, package = "purps")
   data <- readxl::read_excel(path, range = row$range, 
                   sheet = ifelse(row$sheet == "", NULL, row$sheet))
   return(data)
}

list_data <- lapply(split(Files, seq(nrow(Files))), readFiles)

要命名列表，您可以執行以下操作：

names(list_data) <- Files$name