循环遍历目录子文件夹并将结果保存到 R 子文件夹中的另一个目录答案

【问题标题】：Loopin through directories subfolder and save result to other directory in subfolders in R循环遍历目录子文件夹并将结果保存到 R 子文件夹中的另一个目录
【发布时间】：2018-07-20 22:57:58
【问题描述】：

在 R 中，我循环浏览一个文件夹并将 netCDF 文件加载到光栅堆栈中。然后我进行计算并将结果作为多波段 tiff 保存到不同目录中的另一个文件夹中。

问题是，我有几个文件夹，里面有几个 netCDF 文件，我想让代码更有效率。 1.) 遍历目录中的子文件夹并加载 cetCDF 文件 2.) 遍历输出目录中的子文件夹并将结果保存到光盘

什么是执行此操作的有效方法？也许是一个功能？我想它并没有那么复杂，但是我对太多的 for 循环有点困惑......

我附上了我现在所做的工作示例。

files<- list.files(path= paste(wd,"/nc_in/tmax_rcp85/", sep=""), pattern = 'nc$', full.names=TRUE)

# loop through netCDF files and create a raster stack
for (i in 1:length(files)){
  ras<- stack(files[i])
  print(ras)

  outnam<- basename(files[[i]]) # generate output name
  outnam<- sub('\\.nc$', '', outnam)

  results<- stack() # create temp stack of results

  #loop through raster stack and downscale monthly mean averages
  for (r in 1:nlayers(ras)){

    # doing some stuff with each raster in the satck

    # update results temp raster stack
    results <- stack(results, downscale)

  }

  # save downscaled rster stack to disc
  writeRaster(results, file=paste0(getwd(),"/ds_results/tmax_rcp85_ds/",sub('\\.nc$', '', outnam),"_ds",".tif", sep = ""), options="INTERLEAVE=BAND", overwrite=TRUE)
  rm(results) # clear temp stack of results

}
removeTmpFiles(0.1)

【问题讨论】：

标签： r loops subdirectory

【解决方案1】：

我在list.files() 中使用recursive=T 解决了这个问题然后我将生成的 Tiff 保存到包含一些参考信息的同一目录中...

files<- list.files(path= paste(wd,"/nc_in/", sep=""), pattern = 'nc$', full.names=TRUE, recursive=T)

# loop through netCDF files and create a raster stack
for (i in 1:length(files)){
  ras<- stack(files[i])
  print(ras)

  outnam<- basename(files[[i]]) # generate output name
  outnam<- sub('\\.nc$', '', outnam)

  outdir <- dirname(files[[i]])
  Split <- strsplit(outdir, "//")
  lDir<- Split[[1]][length(Split[[1]])]

  results<- stack() # create tem stack of results

  #loop through raster stack and downscale monthly mean averages
  for (r in 1:nlayers(ras)){

    # doing some stuff with each raster in the satck


    # update results raster stack
    results <- stack(results, downscale)

  }

  print(paste("Writing multi band GeoTiff: ", outnam, "to:"))
  print(paste0(dirname(files[[i]]),'/', lDir,"_", sub('\\.nc$', '', outnam),"_ds",".tif", sep = ""))

  # save downscaled rster stack to disc
  writeRaster(results, file=paste0(dirname(files[[i]]),'/', lDir,"_", sub('\\.nc$', '', outnam),"_ds",".tif", sep = ""), options="INTERLEAVE=BAND", overwrite=TRUE)
  rm(results) # clear temp stack of results

}
removeTmpFiles(0.1)

【讨论】：

【解决方案2】：

这里有一些建议

fin <- list.files(path= "/nc_in/tmax_rcp85/", pattern = 'nc$', full.names=TRUE)
fout <- sub("/nc_in/", "/ds_results/", sub('\\.nc$', '.tif', fin)) 
# create output directories if they do not exist
x <- lapply(fout, function(i) dir.create(dirname(i), FALSE, TRUE))


downscale <- function(x) {
    # add your code here
    return(x)
}


for (i in 1:length(fin)){
    s <- stack(fin[i])
    for (j in 1:nlayers(s)){
        s[[j]] <- downscale(s[[j]])
    }
    writeRaster(s, file=fout[i], options="INTERLEAVE=BAND", overwrite=TRUE)
}

【讨论】：