Regular Expression to match 3 or more Consecutive Sequential Characters and Consecutive Identical Characters

by

I don’t think you can (easily) use regex for the first case. The second case is easy though:

Pattern pattern = Pattern.compile("([a-z\\d])\\1\\1", Pattern.CASE_INSENSITIVE);

Since \\1 represents part matched by group 1 this will match any sequence of three identical characters that are either within the range a-z or are digits (\d).

Update

To be clear, you can use regex for the first case. However, the pattern is so laborious and ridiculously convoluted that you are better off not doing it at all. Especially if you wanted to REALLY cover all the alphabet. In that case you should probably generate the pattern programmatically by iterating the char codes of the Unicode charset or something like that and generate groupings for every three consecutive characters. However, you should realize that by having generated such a large decision tree for the pattern matcher, the marching performance is bound to suffer (O(n) where n is the number of groups which is the size of the Unicode charset minus 2).

More Related Contents:

  1. What is the use of Pattern.quote method?
  2. Check if string ends with certain pattern
  3. Java regex to match start/end tags causes stack overflow
  4. Find the highest number between two literal strings using a Regular Expression
  5. How to parse a string that contains value only needed partially to an arraylist? [closed]
  6. How to split a string, but also keep the delimiters?
  7. Match multiline text using regular expression
  8. Regex for matching something if it is not preceded by something else
  9. Splitting a string at every n-th character
  10. removing invalid XML characters from a string in java
  11. How do I convert CamelCase into human-readable names in Java?
  12. Extracting pairs of words using String.split()
  13. What is the simplest way to convert a Java string from all caps (words separated by underscores) to CamelCase (no word separators)?
  14. Java String.split() Regex
  15. Java – regular expression finding comments in code
  16. Remove all empty lines
  17. Given a string, generate a regex that can parse *similar* strings
  18. Constructing regex pattern to match sentence
  19. How to handle requests that includes forward slashes (/)?
  20. String.split() *not* on regular expression?
  21. java string split on all non-alphanumeric except apostrophes
  22. Find the first occurrence with Regex
  23. Java String ReplaceAll method giving illegal repetition error?
  24. Can java.util.regex.Pattern do partial matches?
  25. What is a regex “independent non-capturing group”?
  26. Java regex error – Look-behind group does not have an obvious maximum length
  27. Parse Date from String in this format : dd/MM/yyyy [to dd/MM/yyyy]
  28. How can I perform a partial match with java.util.regex.*?
  29. Java replace all square brackets in a string
  30. Replace HTML codes with equivalent characters in Java [duplicate]

Leave a Comment