Question

我有一个数据框，其中一列包含每行中的xlsx文件名，我想读取r中的每一行，然后添加一个列再保存它，所以为了这个目标，我写了一个循环，如： u = data.frame（V1 = c（“a”，“b”，“c”），stringsAsFactors = F）

for(i in 1:nrow(u) ){
  #file name
  dir = paste(u$V1[1], "_",i , ".xlsx" , sep="")
  #reading the file: the problem is here 
  file<-read.xlsx(dir,1)
  #making it as a dataframe
  file.df<-as.data.frame(downloaded.file)
  #Column which will added to the data
  b <- u$V1[i]
  #Adding a column
  result<-cbind(b,file.df)
  # File name
  dir = paste("res" , i , ".txt" , sep="")
  # Writing the result
  write.table(result , file = dir , sep = "\t")
  # Counting the list
  print(i)}

问题在于，当它找不到文件时，显示错误并从循环中出来。但我希望它转到下一行。为此，我写了一个if子句，如

if (file != 0)
      next

但它无法帮助我。有什么想法解决这个问题吗？

Answer 1

u = data.frame(V1 = c("a", "b","c"),stringsAsFactors = F )
require(xlsx)

for(i in 1:nrow(u) ){
  #file name
  files <- list.files(pattern = "\\.xls") # gets both xls and xlsx
  dir = paste(u$V1[1], "_",i , ".xlsx" , sep="")
  #reading the file: the solution is here 
  if(dir %in% files){
    file<-read.xlsx(dir,1)
    #making it as a dataframe
    file.df<-as.data.frame(downloaded.file)
    #Column which will added to the data
    b <- u$V1[i]
    #Adding a column
    result<-cbind(b,file.df)
    # File name
    dir = paste("res" , i , ".txt" , sep="")
    # Writing the result
    write.table(result , file = dir , sep = "\t")
    # Counting the list
    print(i)
  }
}

在循环中读取一些xlsx文件

1 个答案: