文件（文件，“rt”）中的错误：调用函数时“描述”参数无效

Question

我尝试了多种方法来解决它，但我没有想法。 这是我的代码：

pollutantmean <- function(directory, pollutant, id = 1:332){
        filelist <- list.files(path = "directory", pattern = ".csv", full.names = TRUE)
        value <- data.frame()
        
        for (i in id) {
                dat <- read.csv(filelist[i], header = TRUE)
                value <- rbind(value, dat[[pollutant]])
                
        }
        mean(value, na.rm = TRUE)
}

调用函数时遇到的错误是：

pollutantmean("specdata", 'sulfate', 1:10)
Error in file(file, "rt") : invalid 'description' argument 

我不知道错误是什么我也试过traceback() ：

4.file(file, "rt") 

3.read.table(file = file, header = header, sep = sep, quote = quote, 
       dec = dec, fill = fill, comment.char = comment.char, ...) 

2.read.csv(filelist[i], header = TRUE) at pollutantmean.R#6

1.pollutantmean("specdata", "sulfate", 1:10)

Answer 1

如果我正确理解了问题，则以下代码可以工作。

pollutantmean <- function(directory, pollutant, id = 1:332){
  filelist <- list.files(path = directory, pattern = "\\.csv", full.names = TRUE)
  i <- seq(1, min(length(filelist), length(id)))
  value <- lapply(filelist[i], read.csv)
  value <- sapply(value, '[[', pollutant)
  mean(value, na.rm = TRUE)
}

Answer 2

        > dir.exists("~/R/Air Pollution Data - US/Data/specdata/")
        [1] TRUE
        > list.files(list.files(path = ~/R/Air Pollution Data - US/Data/specdata/, 
        pattern = '\\.csv'))
        Error: unexpected '/' in "list.files(list.files(path = ~/"
        > list.files(list.files(path = "~/R/Air Pollution Data - US/Data/specdata/", 
        pattern = '\\.csv'))
        character(0)

结果我得到