Extract an ISBN with regex

Question

I have an extremely long string that I want to parse for a numeric value that occurs after the substring \"ISBN\". However, this grouping of 13 digits can be arranged differ

Answer 1

You can strip out the dashes with string manipulation, or you could use this:

"\\b(?:\\d-?){13}\\b"

It has the added bonus of making sure the string doesn't start or end with -.

Answer 2

Try this:

Pattern.compile("\\d(-?\\d){12}")

Answer 3

Try stripping the dashes out, and regex the new string

Answer 4

Do it in one step with a pattern recognizing everything, and optional dashes between digits. No need to fiddle with ISBN offset + substrings.

ISBN(\d(-?\d){12})

If you want the raw number, strip dashes from the first matched subgroup afterwards. I am not a Java guy so I won't show you code.

Answer 5

Use this pattern:

Pattern.compile("(?:\\d-?){13}")

and strip all dashes from the found isbn number

Answer 6

• Alternative 1:

  pattern.matcher(ISBN.replace("-", ""))
  

• Alternative 2: Something like

  Pattern.compile("(\\d-?){13}")
  

Demo of second alternative:

String ISBN = "ISBN: 123-456-789-112-3, ISBN: 1234567891123";

Pattern pattern = Pattern.compile("(\\d-?){13}");
Matcher matcher = pattern.matcher(ISBN);

while (matcher.find())
    System.out.println(matcher.group());

Output:

123-456-789-112-3
1234567891123