# Finding text files in a given path and applying a function to those files

I made a function called "SolveLinearSystem[]" that solves,as its name suggests, a linear system of any amount of variables. It takes the path of a text file as its only argument. The function then proceeds to import and calculate the solution.

I currently have a bunch of files stored as text files individually, P1.txt, P2.txt,...,P15.txt which contain a linear system in them.

Now I need to find a way to query a directory so it shows me all text files in there, and then apply my "SolveLinearSystem[]" to each file.

My ultimate goal would be to create an unknown function that accepts a directory (Unknown[dir_]) as argument and then outputs the solution to each system similar to this:

P1.txt
{-0.385248, 0.236472, 1.03691, 1.10608, 1.14523, -1.51569, 1.14748, \
-0.961359, -1.53681, -0.8193, -0.949131}
P2.txt
{22.3934, -6.33219, -9.6342, 16.3643, -9.68272, -18.3644, -5.3851, \
3.75394, -25.4234, -7.91972, -0.370032}
P3.txt
{0.629152, -1.03705, -1.15584, 1.5237, -0.760991, 1.25683, 2.26095, \
-1.6362, 0.728382, -0.160247, -0.467798, -0.100069, -0.743948, \
0.720801, 0.904125}
...etc.


Which represent the set of solutions to each system. Thanks in advance for your help, guys!

• FileNames["P*.txt"]? Then Import[], use your function, and then use Put[]. – J. M. will be back soon Mar 17 '16 at 2:48

You can change current working directory with SetDirectory, read docs for more info.
From the docs: You can see a list of all files in the current working directory by evaluating FileNames[].
You could Map (docs) SolveLinearSystem[] to the output of FileNames[], once you have set the working directory to the files' location.
• I'd imagine, one ought not to Apply, but rather Map SolveLinearSystem to the output of Filenames[] – LLlAMnYP Mar 17 '16 at 15:29