How to use module to assign functions to a set of imported text files?

Question

I have a lot of text files in my folder (in this example I'm using only 8). I am trying to import all of them and then do calculation on each individual file; I want to use the same notebook without restarting the kernel. So far I managed to import all files in my Mathematica notebook as following:

files = FileNames[NotebookDirectory[] <> "*.txt"];
testList = Import[#, "Data"] & /@ files

the output for testList is basically all data points {x,y} in all 8 text files.

A very large output was generated. Here is a sample of it:
{{{17.333, 2.667}, {28.667, 2.667}, {42, 2.333}, {51.333, 3.667}, {64,
    3.667}, {77.333, 5.333}, {89.333, 5}, {100.667, 5.667}, {94.333, 
   16.667}, <<2174>>, {760.333, 669.333}, {771.333, 676}, {782, 
   669}, {792, 675.333}, {802, 668.667}, {761.333, 679.667}, {782.333,
    680.667}, {803.333, 680.667}}, <<6>>, {<<1>>}}

The output for files is:

{"/Users/Desktop/test_automation/400nm_8/8_400nm8_noxy.txt", 

  "/Users/Desktop/test_automation/400nm_8/1_400nm8.txt", 

  "/Users/Desktop/test_automation/400nm_8/2_400nm8.txt", 

  "/Users/Desktop/test_automation/400nm_8/3_400nm8.txt", 

  "/Users/Desktop/test_automation/400nm_8/4_400nm8.txt", 

  "/Users/Desktop/test_automation/400nm_8/5_400nm8.txt", 

  "/Users/Desktop/test_automation/400nm_8/6_400nm8.txt", 

  "/Users/Desktop/test_automation/400nm_8/7_400nm8.txt"}

I can access individual files using:

file2 = ReadList["/Users/Desktop/test_automation/400nm_8/1_400nm8.txt"]

The original file consists of two columns and multiple rows in for of {x,y} but ReadList outputs all in form of a list not a table with two columns i.e.

{272.5, 1636.69, 2744.44, 4561.31, 3469.94, 5444.25,......}

, so I tried:

File2Table = Table[{file2[[i]][[1]], file2[[i]][[2]]}, {i, 1, Length[file2]}]

I get this error: Part::partd: Part specification 1636.69[[1]] is longer than depth of object.>> General::stop: Further output of Part::partd will be suppressed during this calculation. >>

So first question is how can I get the data files in two columns?

Next, I would like to loop the whole process so that I don't have to copy and paste my code 8 times for each individual file. And since I have a code where I do some calculation for a single text file, I don't know how to define my variables and file names such that Mathematica automatically does calculation for a general case.

Someone suggested to use Module to define functions in order to do automation.

Thanks a lot for your help

Answer 1

Next, I would like to loop the whole process so that I don't have to copy and paste my code 8 times for each individual file.

Since Import[..., "Data"] worked for you, why not use that?

Something like

 SetDirectory[NotebookDirectory[]]

And now define, in separate cell, a module to process each file

processFile[fileName_]:=Module[{data},
    data=Import[fileName,"Data"];
    (*add whatever processing needed here *)
]

And now call the above for each file.

files = FileNames[NotebookDirectory[] <> "*.txt"];
Do[
   Print["Processing file ", files[[n]]];
   processFile[files[[n]]]
   ,
   {n, 1, Length[files]}
 ]