Regular Expression - Set of Values

[Scott Selikoff]

Hi All,

I get a huge headache whenever I try to use even basic Java regular expression matching (mostly because online examples never seem to be close to what I need), but I thought rather than doing things with lots of substring/indexof commands, I thought I'd give regex a shot.

Assume you have a string of the following format:
...Grid={t:200, b:300, r:1, o:32}...

Where "..." can be any non-structured text other than the format of the string you're matching. How would you use regular expressions to read the four integer values: 200, 300, 1, 32?

Again, I could use a lot of substring/indexof to do it, but is there a simple way to use regular expressions to get the values? Also, I know you can use the split command (on the commas, then on the :'s), but again this seems like a lot of objects created for a small string (the parsing will be executed millions of times).
[ January 07, 2008: Message edited by: Scott Selikoff ]

[Eric Pascarello]

If you can guarantee the spaces it would be something like this:

 
yourString.replace(".*Grid={t:(\\d+), b:(\\d+), r:(\\d+), o:(\\d+)}.*","$1,$2,$3,$4");

Eric

[edit - switched \n to \d]
[ January 07, 2008: Message edited by: Eric Pascarello ]

[Scott Selikoff]

I'm not sure I follow, basically I would have multiple lines such as:

...Grid={t:200, b:300, r:1, o:32}...
...Grid={t:3040, b:10, r:994, o:94}...
...Grid={t:592, b:5000, r:34, o:942}...
...Grid={t:489, b:400, r:599, o:342}...

And I want to quickly read the values in each set in into array such as short[4].
[ January 07, 2008: Message edited by: Scott Selikoff ]

[Scott Selikoff]

To be precise my goals are:

1) to be able to find this exact pattern in a large string

2) to be able to quickly parse the integer values contained within the matching string

[Marc Peabody]

Never mind
[ January 07, 2008: Message edited by: Marc Peabody ]

[Eric Pascarello]

Ah, typed it real quick \n is a line feed should be \\d

".*Grid={t:(\\d+), b:(\\d+), r:(\\d+), o:(\\d+)}.*"

Eric
[ January 07, 2008: Message edited by: Eric Pascarello ]

[Scott Selikoff]

Hey Eric,

I don't get the function of the replace command. I'm trying to find the values, not replace them. How would you use the code to read the values?

[Eric Pascarello]

String foo = yourString.replace();

would have foo = "###,###,###,###";

You could split it and have your array.

I am not the greatest at Java so not sure if there is another way of using match or something similiar to get the values into an array.

Eric

[Jeanne Boyarsky]

To get results from Eric's regexp:

Pattern p = Pattern.compile(<what Eric wrote> :wink: ;
Matcher m = p.matcher(value);
 
while (m.find()) {
  String t = m.group(1);
  String b = m.group(2);
  String r = m.group(3);
  String o = m.group(4);
}

[edited to disabled smilies]
[ January 07, 2008: Message edited by: Jeanne Boyarsky ]

[Jeanne Boyarsky]

Eric got his reply in first, but mine still makes sense. Cool!

[Scott Selikoff]

Lol, thanks everyone. One of the things I was missing was to call group() with different input arguments. The full running code that matches the pattern and outputs the info is:

String inputStr = "skadladls.\\ad.Grid={t:200, b:300, r:1, o:32}asdjajdsa";
String patternStr = "Grid=\\{t  :(   \\d+), b  :(   \\d+), r  :(   \\d+), o  :(   \\d+)\\}";
Pattern pattern = Pattern.compile(patternStr);
Matcher matcher = pattern.matcher(inputStr);
while(matcher.find()) {
     // Parse value
     short t = Short.parseShort(matcher.group(1));
     short b = Short.parseShort(matcher.group(2));
     short r = Short.parseShort(matcher.group(3));
     short o = Short.parseShort(matcher.group(4));
    
     // Debug output
     System.out.println(t+","+b+","+r+","+o);
}

[ January 07, 2008: Message edited by: Scott Selikoff ]

[Scott Selikoff]

BTW, the double escaping of "\" is annoying in java+regex!

[Tim Holloway]

Originally posted by Scott Selikoff:
BTW, the double escaping of "\" is annoying in java+regex!

This is, alas, because both Java and regexes (and Unix in general) use the same escape character.

At least Eclipse can take an escaped regex string and java-escape it. Small consolation, but better than none.