如何在多个文件或目录中的所有文件上运行相同的代码 [英] How to run same code on multiple files, or all files in directory

问题描述

所以我对编码非常陌生，最近写了一个涉及R和sox的小程序.看起来像这样

so I am very new to coding and recently wrote a little program that involved R and sox. It looked like this

file <- "test.mp3"

testSox = paste("sox ",file," -n spectrogram -o ",file,".png stats",sep='')
sox = system(testSox, intern = TRUE)
print(sox)

现在，我不想在代码中手动分配一个文件，而是想让此代码自动读取文件夹中的所有mp3.这可能吗?任何帮助将不胜感激.谢谢！

Now, instead of assigning the one file manually within the code, I would just like to have this code read through all the mp3s in a folder automatically. Is this possible? Any help would be greatly appreciated. Thanks!

实际上，我应该补充一点，我尝试了list.files，但是在运行system()命令时，我得到了

Actually, I should add that I tried list.files, but when it comes to running the system() command, I get

系统错误(命令(如as.integer(flag)，f，stdout，stderr):字符串应作为第一个参数"

"Error in system(command, as.integer(flag), f, stdout, stderr) : character string expected as first argument"

这是我尝试过的list.files代码:

Here's the list.files code I tried:

> temp = list.files(path = ".", pattern=".mp3")
> 
> file <- temp
> 
> firstSox = paste("sox ",file," -n spectrogram -o ",file,".png stats",sep='')
> sox = system(firstSox, intern = TRUE)
Error in system(command, as.integer(flag), f, stdout, stderr) : 
  character string expected as first argument
> print(sox)

我猜这不是正确的路线吗?因为我基本上需要用temp数组中的每个mp3替换firstSox行中的文件".所以不要运行:

I'm guessing this is not the correct route to go? Because I basically need to replace 'file' in the firstSox line with each mp3 that's in the temp array. So instead of running:

file <- "test.mp3"

...我想让它为文件夹中的每个文件每次都重新分配... ，因此它以test.mp3，然后是1.mp3的方式运行2.mp3，然后是3.mp，等等.

...I would just like to have it re-assign each time for every file in the folder..., so it runs through as test.mp3, then 1.mp3, then 2.mp3, then 3.mp, etc.

我已经搜寻过网，就像感觉自己撞到了砖墙一样.如评论中所述，我已经阅读了循环，但是由于某些原因，我无法将精力集中在如何将其结合到我编写的内容中.我觉得我只需要一个人至少向我展示一下方式，或者甚至给我写一个例子，这样我就可以全神贯注.非常感谢您的帮助以及关于我做错了什么并且可以纠正的任何提示.谢谢.

I've scoured the net, and just feel like I've hit a brick wall. As stated in the comments, I've read up on loops, but for some reason I can't wrap my head around how to incorporate it into what I have written. I feel like I just need someone to show me at least the way, or maybe even write me an example so I can wrap my head around it. Would greatly appreciate help and any tips on what I'm doing wrong and could correct. Thanks.

推荐答案

尝试以下代码.我使用dir()而不是list.files，只是因为我发现它更容易.请记住，在R中有很多方法可以执行相同的操作.

Try the below code. I am using dir() instead of list.files, just because I find it easier. Remember there are many ways to do the same thing in R.

files <- dir(path = ".",pattern = ".mp3") #Get all the mp3 files

for(f in files) {     #Loop over the mp3 files one at a time

    firstSox = paste("sox ",f," -n spectrogram -o ",f,".png stats",sep='')
    sox = system(firstSox, intern = TRUE)
    print(sox)

}

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