CODEWITHSUNDEEP
regexscala
Ophelia
Ophelia

Reputation: 569

Check if string has same characters in a row

I need to find if there are dots in the string in a row. For example

df...fd

This is not valid. But this

d.f.d.d

Is. I am not so strong with regulars expression, does anyone has an idea how to do this? In scala.

Upvotes: 0

Views: 1136

Answers (2)

Dylan
Dylan

Reputation: 13922

A general-purpose solution that works not only on Strings, but on other collection types, is to use the sliding method. It basically slides a fixed-size window over the collection, returning an iterator of those windows.

// string example
val s = "df..fd"
s.sliding(2) contains ".."

// list example
val list = List(1,2,3,4,5,6,2,3,7)
list.sliding(3) contains List(6,2,3)

Upvotes: 3

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 627536

I'd say contains is really the best way to check something like 2 consecutive known characters. If you insist on a regex, here is a sample code (remember that you need to double-escape the dot to match a literal dot):

  val pattern = "\\.{2}".r
  val str = "df..d"
  println(pattern findFirstIn str)

  val pattern2 = "\\.{2}".r
  val str2 = "df.f.d"
  println(pattern2 findFirstIn str2)

  println("df...fd - Офелия".contains("..")) 
  println("df.f.fd - Офелия".contains(".."))

Output:

Some(..)                                                                                                                                                            
None                                                                                                                                                                
true                                                                                                                                                                
false

Upvotes: 2

Related Questions