Joining a list of lists together when generated from a table

Question

I'm batch importing some summary files for analysis

SummaryFileList = FileNames["*.csv*"];
AllSummaryFiles = 
Table[
        SummaryFile = 
        Import[SummaryFileList [[i]]],
        {i, 1, NumberOfSummaryFiles}
     ]

Which will produce

{AllSummaryFiles[[1]], AllSummaryFiles[[2]],...,AllSummaryFiles [[i]] }

I'd like to join the output of these tables, at the moment the only way to achieve the desired result is to manualy choose each element of the list of lists as:

Join[AllSummaryFiles[[1]], AllSummaryFiles[[2]],AllSummaryFiles[[3]]]

The problem is obviously the outer brackets of the table output is there a way to acheive the above result without manually picking out the induvidual list.

---

Essentially, if I import all my summary files sequentially I want to join them all together so that they form a big long list in the order in which they were imported.

Answer 1

Try with:

Join @@ Import["*.csv"]

also, are you sure you want the * after csv?

Some explanation of the code above:

Import["*.csv"]

imports all the files above as a list: if you have three .csv files (1.csv,2.csv,3.csv), the output will be

{file_data1,file_data2,file_data3}

This would be equivalent of your code:

SummaryFileList = FileNames["*.csv"];
NumberOfSummaryFiles = Length[SummaryFileList];
AllSummaryFiles = Table[
   Import[SummaryFileList [[i]]],
   {i, 1, NumberOfSummaryFiles}
]

which, however, would read better as:

SummaryFileList = FileNames["*.csv"];
AllSummaryFiles = Table[
   Import[i],
   {i, 1, SummaryFileList}
]

In both cases, the Table loop is redundant as Import deals with many files automatically, hence one should use just Import["*.csv"]

You then want to Join your files: the way to do it is:

Join @@ AllSummaryFiles

which replicates you example:

Join[AllSummaryFiles[[1]], AllSummaryFiles[[2]],AllSummaryFiles[[3]]]

for a generic length of the list AllSummaryFiles

As obvious, it's much more convenient (and also efficient) to type only Join @@ Import["*.csv"] rather than the whole Table loop, unless you have a specific reason for doing so.