Get List of files from directory in Scala

Question

I have a directory "/local/dath/mi/" which is including many files

03_ssa_fruits.csv
03_ssa_can.csv
03_ssa_veg.csv
sxattru.csv
sxprod.csv
sxstore.csv

I need to extract the list of specific files from that directory :

/local/dath/mi/03_ssa_fruits.csv
/local/dath/mi/03_ssa_can.csv
/local/dath/mi/03_ssa_veg.csv

I have tried the below code ,but it is not working.What I am doing wrong .Can anyone help me

def getListOfFiles(dir: String , naming: String): List[String] = {
      File(dir).toJava.listFiles.filter(_.isFile).toList.filter { file =>
        file.getName.startsWith("03_ss*")
      }.map(_.toString)
    }


   val listOfFile = getListOfFiles(parentDir, File(data.salFilePath).toJava.getName())

look into documentation docs.oracle.com/javase/8/docs/api/java/lang/… String object method startsWith has no support of regexp including wildcard so you need to specify just prefix 03_ss — ProblemSlover
– ProblemSlover, Commented Jan 9, 2018 at 6:04
os-lib is the best modern solution for performing filesystem operations like this with Scala. os-lib makes listing files so much easier and hides all the complexity of the underlying Java libs. See my answer for more details. — Powers
– Powers, Commented Dec 14, 2020 at 13:25

marc_s · Accepted Answer · 2024-05-19 06:17:09Z

16

Here is a simple example

import java.io.File

def getListOfFiles(dir: String): List[String] = {
  val file = new File(dir)
  file.listFiles.filter(_.isFile)
    .filter(_.getName.startsWith("03_ss"))
    .map(_.getPath).toList
}
getListOfFiles("directory path")

Hope this helps!

edited May 19, 2024 at 6:17

marc_s

760k186 gold badges1.4k silver badges1.5k bronze badges

answered Jan 9, 2018 at 6:10

koiralo

23.2k6 gold badges57 silver badges77 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Powers · Accepted Answer · 2020-12-14 13:22:30Z

os-lib is the easiest, most elegant way to perform Scala filesystem operations.

Here's how to list the files that start with "03_ss":

os.list(os.pwd/"local_data").filter(_.segments.toList.last.startsWith("03_ssa"))

This solution is powerful because it lets you perform additional filesystem operations on the files that start with "03_ssa". You can move these files to an other directory, get the file sizes, rename them, delete them, whatever you want.

It's not like the other solutions that simply returns a list of strings. See here for more info on how to harness the power of os-lib.

Here's the code snippet to setup a folder with OP's files if you'd like to experiment on your own machine:

os.makeDir(os.pwd/"local_data")
os.write(os.pwd/"local_data"/"03_ssa_fruits.csv", "")
os.write(os.pwd/"local_data"/"03_ssa_can.csv", "")
os.write(os.pwd/"local_data"/"03_ssa_veg.csv", "")
os.write(os.pwd/"local_data"/"sxattru.csv", "")
os.write(os.pwd/"local_data"/"sxprod.csv", "")
os.write(os.pwd/"local_data"/"sxstore.csv", "")

sarveshseri · Accepted Answer · 2018-01-09 06:56:39Z

0

def pathStringToPath(pathString: String): Path = Paths.get(pathString)

def pathStringToDir(pathString: String): Option[File] = pathToDir(pathStringToPath(pathString))

def pathToDir(path: Path): Option[File] = {
  val file = path.toFile
  file.isDirectory match {
    case true => Some(file)
    case false => None
  }
}

def filesInDir(pathString: String): List[File] = {
  val dirOption = pathStringToDir(pathString)
  dirOption.fold(List.empty[File])(dir => dir.listFiles().toList)
}

def filesWithPrefixInDir(dirPathString: String, fileNamePrefix: String): List[File] =
  filesInDir(dirPathString).filter(file => file.getName.startsWith(fileNamePrefix))

filesWithPrefixInDir(parentDir, "03_ss")

answered Jan 9, 2018 at 6:56

sarveshseri

14k30 silver badges50 bronze badges

Comments

eriel marimon · Accepted Answer · 2018-04-30 17:26:33Z

0

def fetchFilesFromLocalDirectory(path : String) : List[File] = {
        val path = Paths.get(path)

        val file = path.toFile
        if(file.isDirectory){
            file.listFiles().filter(_.getName.endsWith(".txt")).toList
        }else List[File]() // TODO: If is not a directory, it should throw an error
    }

answered Apr 30, 2018 at 17:26

eriel marimon

1,3801 gold badge19 silver badges32 bronze badges

Collectives™ on Stack Overflow

Get List of files from directory in Scala

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related