CODEWITHSUNDEEP
regexscala
Pluto
Pluto

Reputation: 37

Extracting part of a file path

Using Scala, I am trying to extract a value from a path e.g.

val path = hdfs://aloha/data/8907yhb/folders/folder=2319/

What regex can I use for [extracting part]

I have tried it at https://regexr.com/

[I've tried different expressions]

(https://i.sstatic.net/pvgVX.png)

"=[0-9]*"

I didn't get exactly what I expected.

The best result I got:

=2319

but I need to get only

2319

Upvotes: 2

Views: 119

Answers (2)

The fourth bird
The fourth bird

Reputation: 163362

You can use a capture group, and repeat matching the digits 1 or more times to prevent empty matches:

=([0-9]+)

See a regex demo and a Scala demo.

For example:

val path = "hdfs://aloha/data/8907yhb/folders/folder=2319/"
val pattern = "=([0-9]+)".r

val result = pattern.findFirstMatchIn(path) match {
  case Some(v) => v.group(1)
  case _ => "No match"
}

println(result)

Or with \d to match a digit:

val pattern = "=(\\d+)".r

Output

2319

Upvotes: 1

Alex
Alex

Reputation: 7926

You can use look behind (?<=...) pattern.

(?<==)[0-9]* // matches zero or more digits but only if they follow the '=' sign.

Example:

scala> "(?<==)[0-9]*".r.findAllIn("hdfs://aloha/data/8907yhb/folders/folder=2319/").toList

List(2319)

Upvotes: 2

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