The regular expressions are useful in finding the patterns in the data. These operations are basically used to find and replace operations performed on the string. In Scala, a string is changed into a regular expressing by using the .r method. (.r) is denoted as Regex that is used for text parsing and present in scala. util.matching package.

The following is an example of a regular expression pattern in which we will use Regex(regular expression) to make sure a password contains a number. Download the program and run it from the Scala shell.

```
```
import scala.util.matching.Regex
val regularexp: Regex = "[0-9]".r
regularexp.findFirstMatchIn("awesomepassword") match {
case Some(_) => println("Password OK")
case None => println("Password should contain a number")
}

__Output__

Click Here To Download Code File.

__Scala Regular Expressions__

__Scala Regular Expressions__

The following is the list of regular expression operators that are supported in Scala.

Expression | Actions |
---|---|

^ | This expression matches the beginning of the line. |

$ | This expression matches the end of the line. |

. | It matches any of the single characters beside newline. |

[...] | This expression matches any single character in brackets. |

[^...] | This expression matches any single character, not in brackets. |

\\A | Beginning of the entire string. |

\\z | End of the entire string. |

\\Z | It represents the end of the entire string. |

re* | This expression matches 0 or more occurrences of the preceding expression. |

re+ | This expression matches 1 or more of the previous thing |

re? | It matches 0 or 1 event of the expression. |

re{ r} | This expression matches exactly r number of occurrences of the preceding expression. |

re{ y,} | This expression matches y or more occurrences of the preceding expression. |

re{ y, z} | This expression matches at least y and at most z occurrences of the preceding expression. |

a|b | This expression matches either a or b. |

(re) | This expression Groups regular expressions and remembers matched text. |

(?: re) | This expression Groups regular expressions without remembering matched text. |

(?> re) | This expression matches an independent pattern without backtracking. |

\\w | This expression matches word characters. |

\\W | This expression matches nonword characters. |

\\s | This expression matches whitespace. Equivalent to [\t\n\r\f]. |

\\S | This expression matches non-whitespace. |

\\d | This expression matches digits. Equivalent to [0-9]. |

\\D | This expression matches non-digits. |

\\A | This expression matches the beginning of the string. |

\\Z | This expression matches the end of the string. |

\\z | This expression matches the end of the string. |

\\G | It indicates the point where the last match was finished. |

\\n | Back-reference to capture group number "n" |

\\b | This expression matches word boundaries when outside brackets. Matches backspace (0x08) when inside brackets. |

\\B | This expression matches nonword boundaries. |

\\n, \\t, etc. | This expression matches newlines, carriage returns, tabs, etc. |

\\Q | This expression is used to quote all characters till \\E. |