Solved

Java replaceAll regex

Posted on 2009-04-02
7
1,605 Views
Last Modified: 2013-11-23

 Hi Experts,
 
    I want to replace the following string embeded in an input line
   AFunctionName[startPosition , endPosition]  
   with
   SUBSTR(AFunctionName, startPosition , endPosition)
 
   match requirements:
   1.  space in AFunctionName[startPosition , endPosition],  before and after comma ","  is option;
   2. All names, AFunctionName, startPosition, endPosition are made of  word characters

   I wrote a method to parse it doesn't work, any help is appreciated.

0
Comment
Question by:SarahDeng
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 3
7 Comments
 
LVL 40

Accepted Solution

by:
Richard Quadling earned 300 total points
ID: 24055081
Try this ...
StringBuffer resultString = new StringBuffer();
try {
	Pattern regex = Pattern.compile("(\\w+)\\[(\\w+) , (\\w+)\\]", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE | Pattern.MULTILINE);
	Matcher regexMatcher = regex.matcher(subjectString);
	while (regexMatcher.find()) {
		try {
			// You can vary the replacement text for each match on-the-fly
			regexMatcher.appendReplacement(resultString, "SUBSTR($1, $2, $3)");
		} catch (IllegalStateException ex) {
			// appendReplacement() called without a prior successful call to find()
		} catch (IllegalArgumentException ex) {
			// Syntax error in the replacement text (unescaped $ signs?)
		} catch (IndexOutOfBoundsException ex) {
			// Non-existent backreference used the replacement text
		} 
	}
	regexMatcher.appendTail(resultString);
} catch (PatternSyntaxException ex) {
	// Syntax error in the regular expression
}

Open in new window

0
 

Author Closing Comment

by:SarahDeng
ID: 31566024
Can't expect better and quicker than this!
0
 

Author Comment

by:SarahDeng
ID: 24055341
Hi RQuadling,
Oops! there is one exception.
It doesn't work when there is no space before and after the ","
example:
 No space in AFunctionName[startPosition,endPosition],  before and after comma ","
I change the expression to the following, it doesn't work for me.  Could you help again? Thanks!
 "(\\w+)\\[(\\w+)(\\s*),(\\s*) (\\w+)\\]",
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 40

Expert Comment

by:Richard Quadling
ID: 24055392
Try this ...
StringBuffer resultString = new StringBuffer();
try {
	Pattern regex = Pattern.compile("(\\w+)\\[(\\w+)\\s+?,\\s+?(\\w+)\\]", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE | Pattern.MULTILINE);
	Matcher regexMatcher = regex.matcher(subjectString);
	while (regexMatcher.find()) {
		try {
			// You can vary the replacement text for each match on-the-fly
			regexMatcher.appendReplacement(resultString, "SUBSTR($1, $2, $3)");
		} catch (IllegalStateException ex) {
			// appendReplacement() called without a prior successful call to find()
		} catch (IllegalArgumentException ex) {
			// Syntax error in the replacement text (unescaped $ signs?)
		} catch (IndexOutOfBoundsException ex) {
			// Non-existent backreference used the replacement text
		} 
	}
	regexMatcher.appendTail(resultString);
} catch (PatternSyntaxException ex) {
	// Syntax error in the regular expression
}

Open in new window

0
 

Author Comment

by:SarahDeng
ID: 24055491
I tried... It doesn't work with the case that no space before and after the ","
Like this.
string_variable[startPosition,endPostion]

0
 

Author Comment

by:SarahDeng
ID: 24055529
Changed the expression to
"(\\w+)\\[(\\w+)\\s*,\\s*(\\w+)\\]"
it works.
Can you explain why?
0
 
LVL 40

Expert Comment

by:Richard Quadling
ID: 24057754
Ah Yes.

\s+\s*

Options: case insensitive; ^ and $ match at line breaks

Match a single character that is a whitespace character (spaces, tabs, line breaks, etc.) «\s+?»
   Between one and unlimited times, as few times as possible, expanding as needed (lazy) «+?»

Match a single character that is a whitespace character (spaces, tabs, line breaks, etc.) «\s*»
   Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»


I was assuming at least 1 space. Sorry.
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
CSV file parsing thru Java 13 54
Crystal Reports Licensing Questions 4 87
What is the use of Forwarding Class in java 1 54
Regex for string 2 44
Java had always been an easily readable and understandable language.  Some relatively recent changes in the language seem to be changing this pretty fast, and anyone that had not seen any Java code for the last 5 years will possibly have issues unde…
This was posted to the Netbeans forum a Feb, 2010 and I also sent it to Verisign. Who didn't help much in my struggles to get my application signed. ------------------------- Start The idea here is to target your cell phones with the correct…
This tutorial covers a practical example of lazy loading technique and early loading technique in a Singleton Design Pattern.
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …
Suggested Courses

751 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question