Arrays 在R中的循环代码块内创建全局变量

我是R新手，正在尝试访问循环外的数据

# List of 100 stock data
a <-c ("one", "two", "three", "four",...)
i = 1
while (i <= length(a)) {
  # make a list_element.csv to be accessed from local storage
  formated_path <-paste(a[i], ".csv")
    if (!file.exists(formated_path)) {
      output <- paste("Data for ", a[i], "Not found!")
      print(output)
    } else {
      print("found")     
      a[i] <- read.csv(formated_path, header = TRUE)

      # I have tried to change the name of the array to
      # correspond  to the element name but no luck as
      paste(a[i], "_stock") <-read.csv(formated_path, header = TRUE)
      return(a[i])
      i = i + 1
    }
  }

---

如果你真的想继续你的方法，你正在寻找的函数叫做

assign

。但是，我想鼓励您以不同的方式思考您的问题：

a <- c("one", "two", "three", "four")
fileNames <- paste0(a, ".csv")
csvList <- lapply(fileNames, read.csv)
str(csvList)

---

并在调用

lappy

时使用它。您可以在中找到详细的解释

看起来您正在尝试加载多个

.csv

文件？如果是这样的话，在R中有更简单的方法。这个答案是最简单的：

a <- c("one", "two", "three", "four")
fileNames <- paste0(a, ".csv")
csvList <- lapply(fileNames, read.csv)
str(csvList)

myReadCsv <- function(fileName) {
  if (file.exists(fileName){
    read.csv(fileName)
  } else {
    message("File does not exist and is ignored")
    NULL
  }
}