R 中的输出格式

Question

我是 R 新手，尝试对多组数据进行相关性分析。我能够进行分析，但我试图弄清楚如何输出数据结果。我想要如下输出：

 NAME,COR1,COR2
 ....,....,....
 ....,....,....

如果我可以将这样的文件写入输出，那么我可以根据需要对其进行后期处理。我的处理脚本如下所示：

run_analysis <- function(logfile, name)
{
  preds <- read.table(logfile, header=T, sep=",")

  # do something with the data: create some_col, another_col, etc.

  result1 <- cor(some_col, another_col)
  result1 <- cor(some_col2, another_col2)

  # somehow output name,result1,result2 to a CSV file
 }

args <- commandArgs(trailingOnly = TRUE)
date <- args[1]
basepath <- args[2]
logbase <- paste(basepath, date, sep="/")
logfile_pattern <- paste( "*", date, "csv", sep=".")
logfiles <- list.files(path=logbase, pattern=logfile_pattern)

for (f in logfiles) {
  name = unlist(strsplit(f,"\\."))[1]
  logfile = paste(logbase, f, sep="/")
  run_analysis(logfile, name)
}

有没有一种简单的方法来创建空白数据框，然后逐行向其中添加数据？

Answer 1

您看过 R 中用于将数据写入文件的函数吗？例如，write.csv。也许是这样的：

rs <- data.frame(name = name, COR1 = result1, COR2 = result2)
write.csv(rs,"path/to/file",append = TRUE,...)

Answer 2

我喜欢使用 foreach 库来做这类事情：

library(foreach)

run_analysis <- function(logfile, name) {
  preds <- read.table(logfile, header=T, sep=",")
  # do something with the data: create some_col, another_col, etc.
  result1 <- cor(some_col, another_col)
  result2 <- cor(some_col2, another_col2)

  # Return one row of results.
  data.frame(name=name, cor1=result1, cor2=result2)
}

args <- commandArgs(trailingOnly = TRUE)
date <- args[1]
basepath <- args[2]
logbase <- paste(basepath, date, sep="/")
logfile_pattern <- paste( "*", date, "csv", sep=".")
logfiles <- list.files(path=logbase, pattern=logfile_pattern)

## Collect results from run_analysis into a table, by rows.
dat <- foreach (f=logfiles, .combine="rbind") %do% {
  name = unlist(strsplit(f,"\\."))[1]
  logfile = paste(logbase, f, sep="/")
  run_analysis(logfile, name)
}

## Write output.
write.csv(dat, "output.dat", quote=FALSE)

它的作用是在每次调用 run_analysis 时生成一行输出，将它们绑定到一个名为 dat 的表中（对 foreach 调用的 .combine="rbind" 部分会导致 row binding）。然后你可以使用write.csv来获得你想要的输出。