How to create multiple directories given the folder names

Question

I have a list of files, the names of these files are are made of a classgroup and an id `(eg. science_000000001.java)` i am able to get the names of all the files and split them so i am putting the classgroups into one array and the ids in another.. i have it so that the arrays cant have two of the same values. This is the problem, i want to create a directory with these classgroups and ids, an example: ``` science_000000001.java would be in science/000000001/science_000000001.java science_000000002.java would be in science/000000002/science_000000002.java maths_000000001.java would be in maths/000000001/maths_000000001.java ``` but i cannot think of a way to loop through the arrays correctly to create the appropriate directories? Also i am able to create the folders myself, its just getting the correct directories is the problem, does anyone have any ideas?

Accepted Answer

Given:

```
String filename = "science_000000001.java";
```

Then

```
File fullPathFile = new File(filename.replaceAll("(\w+)_(\d+).*", "$1/$2/$0"));
```

gives you the full path of the file, in this case `science/000000001/science_000000001.java`

If you want to create the directory, use this:

```
fullPathFile.getParentFile().mkdirs();
```

How to create multiple directories given the folder names

Solution

Problem