SCJP6 regex issue

by

\d* matches 0 or more digits. So, it will even match empty string before every character and after the last character. First before index 0, then before index 1, and so on.

So, for string ab34ef, it matches following groups:

Index    Group
  0        ""  (Before a)
  1        ""  (Before b)
  2        34  (Matches more than 0 digits this time)
  4        ""  (Before `e` at index 4)
  5        ""  (Before f)
  6        ""  (At the end, after f)

If you use \\d+, then you will get just a single group at 34.

More Related Contents:

  1. What do the characters ((?:(?:(?: mean in pattern-matching? [duplicate]
  2. Java: splitting a comma-separated string but ignoring commas in quotes
  3. Split string with dot as delimiter
  4. Use String.split() with multiple delimiters
  5. Java how to replace 2 or more spaces with single space in string and delete leading and trailing spaces
  6. Java Regex Capturing Groups
  7. Compare one String with multiple values in one expression
  8. Replace the last part of a string
  9. Java equivalent to PHP’s preg_replace_callback
  10. java.lang.StackOverflowError while using a RegEx to Parse big strings
  11. Split regex to extract Strings of contiguous characters
  12. Java regex – overlapping matches
  13. Generic support for ISO 8601 format in Java 6
  14. Find everything between two XML tags with RegEx
  15. Parsing CSV input with a RegEx in java
  16. simple java regex throwing illegalstateexception [duplicate]
  17. Range of valid character for a base 64 encoding
  18. Regex: ?: notation (Question mark and colon notation) [duplicate]
  19. Whats the difference between \z and \Z in a regular expression and when and how do I use it?
  20. Regex for checking if a string is strictly alphanumeric
  21. Java Regex pattern that matches in any online tester but doesn’t in Eclipse
  22. Java Pattern Matcher: create new or reset?
  23. Regular Expression for matching parentheses
  24. Java Regex – Using String’s replaceAll method to replace newlines
  25. Replace a String between two Strings
  26. Does Pattern.compile cache?
  27. Regex to remove spaces between numbers only
  28. Regex Pattern Catastrophic backtracking
  29. Print regex matches in java
  30. regex replace all ignore case

Leave a Comment