performance « Development « Java Regex Q&A

1. How to get good perfomance of Regex in java    stackoverflow.com

Below is example of text:

String id = "A:abc,X:def,F:xyz,A:jkl";

Pattern p = Pattern.compile("(.*,)?[AC]:[^:]+$");
if(p.matcher(id).matches()) {
  System.out.println("Hello world!")
}

2. Best practices for regex performance VS sheer iteration    stackoverflow.com

I was wondering if there are any general guidelines for when to use regex VS "string".contains("anotherString") and/or other String API calls? While above given decision for .contains() is trivial (why bother with ...

3. Why do these regular expressions execute slowly in Java?    stackoverflow.com

I am trying to use regular expressions to determine what format the user have applied when entering input in a textbox.
The regular expressions are as follows:

(\\s?[" + alphabet + "]{9,9})+

4. Regular expression performance in Java -- better few complex or many simple?    stackoverflow.com

I am doing some fairly extensive string manipulations using regular expressions in Java. Currently, I have many blocks of code that look something like:

Matcher m = Pattern.compile("some pattern").matcher(text);
StringBuilder b = new ...

5. Java Regex performance    stackoverflow.com

I'm trying to parse links with Regex with Java. But, i think its getting to slow. For example. To extract all links from:

• http://news.google.com.ar/nwshp?hl=es&tab=wn

6. Java Regular Expression running very slow    stackoverflow.com

I'm trying to use the Daring Fireball Regular Expression for matching URLs in Java, and I've found a URL that causes the evaluation to take forever. I've modified ...

7. Measure Regex Performance    stackoverflow.com

Is there an easy way to measure the performance of all regular expressions within a java application?

8. Time complexity for using regexes?    stackoverflow.com

Possible Duplicate:
What is the complexity of regular expression?

9. Java RegExp: Which is faster: series of simple ones or one complex?    stackoverflow.com

I am writing a program that has to strip pretty long strings of quite a lot of rubbish. I do that using regular expressions, and as my program is rather sensitive ...

10. High performance simple Java regular expressions    stackoverflow.com

Part of the code I'm working on uses a bunch of regular expressions to search for some simple string patterns (e.g., patterns like "foo[0-9]{3,4} bar"). Currently, we use statically-compiled Java Patterns ...

11. Regex in java and its performance compared to indexOf    stackoverflow.com

Please can someone tell me how to match "_" and a period "." excatly one time in a string using regex, Also is it more efficient using indexOf() instead of regex ...

12. RegEx, CharBuffer Vs String performance    coderanch.com

Hi, I am building a module to extract data from text files using the java.util.regex package. I have to process thosands of text documents so performance is a must. I define regular expressions to match regions of the file, and further regular expressions to match fields within those regions. Since the regex package uses the CharSequence interface, more or less I ...

13. performance of java.util.regex    forums.oracle.com

Hi, I wrote [a very simple benchmark|http://mypatterns.free.fr/java/stable/mypatterns/doc/regex.html] for measuring the cost of regex matching, as provided by java.util.regex, and I'm obtaining an overhead between 10 to 13 times(!!) for a very simple regex: "File ([^ ]*) not (found|readable).*!!!" when compared with equivalent hand-coded matching. The questions I have are: - is it a well-known fact that java.util.regex matching can add an ...

14. Severe RegEx Performance Problems    forums.oracle.com

I have written a pretty large set of RegEx operations that run quite speedily on my MacBook Pro, but when I move the code to a Windows server (that will be the final deployment machine), the code runs about 1/1000 as fast. What's going on here? The MacBook Pro is a Core 2 Duo and the Windows machine is a 3.0Ghz ...