Pattern matching help

Hi!
I'm new to pattern matching and need a little code to get me started. I currently have it where the user enters a name and it compares that name to a string pulled from a file using String.indexOf(). If it does not match, it pulls the next name string from the file and trys again until it finds a match or reaches the end of the file.
For example, if I enter "hn smith" it will match to "john smith" in the string pulled from the file.
This works ok, but it would be a lot nicer if the user could enter in
jo.n smith or jo* smith
where it can match parts of the phrase instead of the exact phrase. I have done a slight bit of this in perl, but I am having a harder time in java.
I would appreciate any help. Thank you!

that's good when you know it, but when you are
starting out it is nice to have an example to work
with, one that is explained well, unlike many of the
sites I have visited.http://java.sun.com/docs/books/tutorial/extra/regex/index.html
The very first result from Google is a tutorial that explains regular expressions.

Similar Messages

Regular Expressions (Pattern/Matcher) --- Help

Hi,
I have an regex i.e. Pattern.compile("([0-9])D([0-9])'?(?:([0-9]+)\")?([NSEW])").{code}
It has to exactly match the input e.g *45D15'34"N*
I need to retrieve the values based on grouping.
Group1 = 45 (degree value)
Group2 = 15 (minutes value)
Group3 = 34 (seconds value) ----> this is a non-capturing group
Group4 = N (directions)
The regex works fine for most of longitude/latitude value but I get a StackOverFlow for some. There is a known bug on this http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5050507
According to the bug report, they have said that are many different regex that can trigger the stack overflow....even though the length of my input is not as long as the one posted on the bug report.
I was wondering if anyone could suggest a different way of writing the regex above to avoid the stack over flow.
Thank you in advance

Hi,
I missed the '+' in my original regex Pattern.compile("([0-9]+)D([0-9]+)'?(?:([0-9]+)\")?([NSEW])"){code}.
I have also tried {code} Pattern.compile("(\\d+)D(\\d+)'?(?:(\\d+)\")?([NSEW])");And, the other 2 expressions as suggested by you.
The problem happens when Durham Lat=35D52N Lon=78D47W value is selected from a Jtree(the values are parsed from a xml file to the tree - the xml file has a bout 800 longitude/latitude elements for different cities in the US). It does not happen for other values and If I increment the degree or min by, then the expression works. I am not sure how else i could re-write this exp.
Below is the snippet of the xml file:
<State name="NORTH CAROLINA">
            <City name="Asheville AP"     Lat="35D26'N"     Lon="82D32'W"/>
            <City name="Charlotte AP"     Lat="35D13'N"     Lon="80D56'W"/>
            <City name="Durham"     Lat="35D52'N"     Lon="78D47'W"/>
            <City name="Elizabeth City AP"     Lat="36D16'N"     Lon="76D11'W"/>
            <City name="Fayetteville, Pope AFB" Lat="35D10'N"     Lon="79D01'W"/>
            <City name="Goldsboro,Seymour-Johnson"     Lat="35D20'N"     Lon="77D58'W"/>
            <City name="Greensboro AP (S)"     Lat="36D05'N"     Lon="79D57'W"/>
            <City name="Greenville"     Lat="35D37'N"     Lon="77D25'W"/>
            <City name="Henderson"     Lat="36D22'N"     Lon="78D25'W"/>
            <City name="Hickory"     Lat="35D45'N"     Lon="81D23'W"/>
            <City name="Jacksonville"     Lat="34D50'N"     Lon="77D37'W"/>
            <City name="Lumberton"     Lat="34D37'N"     Lon="79D04'W"/>
            <City name="New Bern AP"     Lat="35D05'N"     Lon="77D03'W"/>
            <City name="Raleigh/Durham AP (S)"     Lat="35D52'N"     Lon="78D47'W"/>
            <City name="Rocky Mount"     Lat="35D58'N"     Lon="77D48'W"/>
            <City name="Wilmington AP"     Lat="34D16'N"     Lon="77D55'W"/>
            <City name="Winston-Salem AP"     Lat="36D08'N"     Lon="80D13'W"/>
        </State>
public final class GeoLine {
    /* Enum for the possible directions of longitude and latitude*/
    public enum Direction {
        N, S, E, W;
        public boolean isLongitude() {
            return (this == E || this == W);
        public boolean isLatitude() {
            return (this == N || this == S);
        public Direction getCanonicalDirection() {
            if (this == S) {
                return Direction.N;
            } else if (this == W) {
                return Direction.E;
            } else {
                return this;
    private final int degree;
    private final int minute;
    private final int second;
    private final Direction dir;
    /* Recognizes longitude and latitude values that has degrees, minutes and seconds i.e. "45D15'34"N
    * or "45D1534"N. The single-quotes for the minutes is optional. And, for the moment we do not support seconds
    * validation although ilog library returns the longitude/latitude with second when NEs and Sub-networks are
    * dragged and dropped on the map.*/
private static final Pattern PATTERN = Pattern.compile("([0-9]+)D([0-9]+)'?(?:([0-9]+)\")?([NSEW])");
    public GeoLine(int degree, int minute, Direction dir) {
        this(degree, minute, 0, dir);
    public GeoLine(int degree, int minute, int second, Direction dir) {
        Log.logInfo(getClass().getSimpleName(), "PAU degree: " + degree + " minute: " + minute + " second: " + second + " direction: " + dir);
        verifyLongitudeLatitude(degree, dir);
        verifyMinute(degree, minute, dir);
        this.degree = degree;
        this.minute = minute;
        this.second = second;
        if (this.degree == 0 && this.minute == 0 && this.second == 0) {
            this.dir = dir.getCanonicalDirection();
        } else {
            this.dir = dir;
    public Direction getDirection() {
        return dir;
    public int getMinute() {
        return minute;
    public int getDegree() {
        return degree;
    public int getSecond() {
        return second;
    public static GeoLine parseLine(String location) {
        * Matcher class will throw java.lang.NullPointerException if a null location
        * is passed, null location validation is not needed.
        Matcher m = PATTERN.matcher(location);
        if(m.matches()) {
            int deg;
            int min;
            int second;
            Direction direction;
            deg = Integer.parseInt(m.group(1));
            min = Integer.parseInt(m.group(2));
            if (m.group(3) == null) {
                second = 0;
            } else {
                second = Integer.parseInt(m.group(3));
            direction = Direction.valueOf(m.group(4));
            return new GeoLine(deg, min, second, direction);
        } else {
            throw new IllegalArgumentException("Invalid location value. Expected format XXDXX'XX\"[NSEW] " + location);
    private void verifyMinute(int deg, int min, Direction direction) {
        /* This validation is to make sure that minute does not exceed 0 if maximum value for latitude == 90
        * or longitude == 180 is specified */
        int maxDeg = direction.isLatitude() ? 90 : 180;
        if(min < 0 || min > 59) {
           throw new NumberFormatException("Minutes is out of range. Value should be less than 60: " + min);
        if (deg == maxDeg && min > 0) {
            throw new NumberFormatException("Degree value " + deg + "D" + direction + " cannot have minute exceeding 0: " + min);
    private void verifyLongitudeLatitude(int valDeg, Direction valDir) {
           int max = valDir.isLatitude() ? 90 : 180;
           if(valDeg < 0 || valDeg > max) {
                throw new NumberFormatException("Degree " + valDeg + valDir + " is invalid");
    public final boolean isLongitude() {
        return dir.isLongitude();
    public final boolean isLatitude() {
        return dir.isLatitude();
    @Override
    public final String toString(){
        if(minute < 10){
            return degree + "D0" + minute + dir;
        } else {
            return degree + "D" + minute + dir;
    @Override
    public boolean equals(Object obj) {
        if (obj instanceof GeoLine) {
            GeoLine other = (GeoLine) obj;
                return (this.degree == other.degree && this.minute == other.minute && this.second == other.second && this.dir == other.dir);
        return false;
    @Override
    public int hashCode() {
        int result = 17;
        result = result * 37 + degree;
        result = result * 37 + minute;
        result = result * 37 + second;
        result = result * 37 + dir.hashCode();
        return result;
}Thank you again.

[Solved]Sed pattern matching help

Ok I have a file like:
foo
cloo
zoo
And I want to have a script where: If it finds a line "foo" in a file, I want it to change the file to be:
foo bar
cloo
zoo
However, if the file already has "bar" appended to the line (as per the second example above), I want it to ignore the line.
A sed line:
sed -i '/foo/ s/$/ bar/' ~/myfile
Will do the trick as far as appending " bar" to lines that say "foo"
but it will also append " bar" to lines that already say "foo bar"
What I need is code that will look for lines that say "foo" and append the " bar", but ignore instances where the " bar" has already been appended.
In English: Find lines that start with "foo" but do not include " bar" and append bar to the end of the line.
I am not married to using sed, but it needs to be something I can toss into a bash script and run. This seems simple, but hours later...
Thanks
Last edited by andrekp (2013-10-03 19:31:53)

Thanks for ALL of your help, everyone. Works great.
Just to show what I was REALLY doing, I run openbox with obmenu-generator and I was trying to have a special menu entry for certain programs that I use a lot so that I could find them easily and immediately. This entailed creating a special category for the program in the respective /usr/share/applications/<program>.desktop file on the "Categories=" line.
A typical line might read:
Categories=GNOME;GTK;Office;Viewer;Graphics;2DGraphics;VectorGraphics;
And I wanted to add my special category, "Favorites" at the end. Leaving out lots of detail, this would allow me to have a special menu item for certain programs. At first I just added it manually like:
Categories=GNOME;GTK;Office;Viewer;Graphics;2DGraphics;VectorGraphics;Favorites
but I found that the <program>.desktop file would get replaced on updates and overwrite my changes every so often. So I figured I'd write a script to do the updating and just run that when I saw the need.
And additional wrinkle was that some programs had the line by default as:
Categories=GNOME;GTK;Office;Viewer;Graphics;2DGraphics;VectorGraphics;
and others as:
Categories=GNOME;GTK;Office;Viewer;Graphics;2DGraphics;VectorGraphics
Note the final ; or lack thereof, so I had to account for that as well. (Actually, I could ignore it and just add ;Favorites to the end, since the system ignored ";;" as being an error - but I wanted to do it cleanly.)
My final code became:
sudo sed -i 's/$Categories.*$;$/\1/;/Favorites/! s/Categories.*$/&;Favorites/' /usr/share/applications/evince.desktop
which first strips off the final ; if found on the Categories line, then adds ;Favorites to the end of that line. I just created a line in a bash script for each program I wanted to form the favorites menu, as above. Works well. May or may not be the best way, but...
Anyway, maybe this will give an idea helpful to someone else.
(Personally, I think it would be nice if the .desktop files, which are really just configuration files, should warn you when they overwrite, but that's probably a losing argument.)
Thanks again,
Andre

Help for image pattern matching

Hello Everyone
I am working for my last year project. In my project I will work on the image processing to find a moving object. I will work by JMF. I have finished to grab a frame from the webcam video clips. Now I need a algorithm to find a Image pattern from the grabed image. But I donot know which algorithm is fine for image pattern matching as well as how can I implement in java. Is anyone know please help me very urgently.
Thank you
Md. Mainul Hasan

If you would like to take a look at http://www.exactfutures.com/index01.htm and http://www.exactfutures.com/index02.htm and http://www.codeproject.com/useritems/activity.asp then these pages and links may well be useful to you. It may not be exactly what you are looking for, but it does point to some examples with source for video analytics, and at the very least they illustrate how to capture & handle the data including a fast movement detection algorithm. If you want to find a specific shape then search the internet for information on chamfer distance transforms - one can use JMF or extend these simple examples to apply those techniques.

RegEx, need help with pattern matching

im going thru a list of Strings...and id like to match some input to it..but the tutorial for regex wont let me find a smaller string within a bigger one if it exists
for example i have a String "java.sun.com" and i want to find "sun" or "java" or "com" or "jav" or ".co"
i think the only way regex will work is if i group the entire thing into
any ideas on how i can manipulate the string into a proper regex pattern so that itll find any of those "searches"
thanks

No, that is not correct. A regex can be constructed to return a match on anything you want. A single character, a newline character, a numeric character and any combination of them. There are limitless possibilities for pattern matching.
See here:
http://java.sun.com/j2se/1.4.1/docs/api/java/util/regex/Pattern.html
Any of the patterns may be compiled into a regex for searching using the matcher.
An alternative is to use the indexOf method of the string class to find what you are looking for.
Example:
String myString = "java.sun.com";
String matchThis = "n.co";
int patternFoundAtThisIndexPosition = myString.indexof(matchThis);patternFoundAtThisIndexPosition will be 7;
or simply:
int index = myString.indexof("sun");index will be 5;

How can I read a template and differentiate if it is a pattern matching template or a geometric matching template?

Hey all,
I would like to know how can I read a template´s information to know if it is a pattern macthing or a geometric matching template?
In my code, users provide templates and the algorithm must match them using pattern matching or geometric matching depending on the template.
At the moment I am doing it by including a P or a G in the name of the file, but I would like to avoid this and read the information from the file.
Any ideas?
Thanks in advance,
Esteban
Solved!
Go to Solution.

Hey Esteban,
you can use the VI "IMAQ Is Vision Info Present 2 VI" to reice the information:
IMAQ Is Vision Info Present 2 VI - NI Vision 2011 for LabVIEW Help - National Instruments
http://zone.ni.com/reference/en-XX/help/370281P-01/imaqvision/imaq_is_vision_info_present_2/
Take a look at the attached VI
Stephan
Attachments:
Determine Pattern type.zip ‏13 KB

Is there a way to turn the pattern matching example in Labview to instead of loading a rectangle around what you want the template to be you can use an image display , I've be trying and can get no where with it

What I want to do is , have two images on image displays and the pass them through the same setup as the pattern matching example to get the number of matches , I have attached what I have done and also given the pattern matching example program as well.
Hope to get answers back soon,
Thanks Alan
Attachments:
screenshot.docx ‏48 KB
Pattern Matching Example.vi ‏100 KB

Hi there!
The example used can be adapted for comparing two images, however the algorithm and coding for finding the differences is more specific to your actual problem. In terms of the loading and displaying of the images, this can be done in the same way.
Once you have some sort of algorithm, then you can automate the learning and matching by simply wiring them in order. (in the example, these are put in case structures as they are waiting on response from the front panel)
I hope that this helps,
Liam A.
National Instruments
Applications Engineer

Mod_security: Access denied with code 405. Pattern match "!(GET|HEAD|POST)

Hi all,
After Cloning facing an issue
mod_security: Access denied with code 405. Pattern match "!(GET|HEAD|POST)"
and not able to get the login prompt
EBS: 12.1.3
DB:11G
Please help as this is urgent.
Regards,
Raj.

Hi Hussein/Srini,
My OS details are as follows
Source OS : OE Linux 5X
Target : REHL
DB : 11.2.0.3
In my previous cloning the R12 login URL was not getting redirected to https from http. This backup was given by client last week and I completed the cloning and post cloning procedures without any error, but unable to login as the page is redirecting to https:/hostname:port/OA_HTML/AppsLogin.
I have done the following so far, but the issue is not getting resolved.
1) Generated JAR files using ADADMIN (Force)
2) Compiled JSP
3) Ran autoconfig multiple times without any error in both db and application tiers.
4) DB alert log did not have any error.
5) Executed relink all from APPL_TOP
6) Able to launch http://XXXXXXXXX:XXXX/forms/frmservlet?
Kindly help me out on this
Regards

Pattern matching for range of numbers

I am facing problem in using a pattern like [200-300] to match any number in the range 200 and 300 inclusive. I wrote following code:
public class RangeTest {
     public static void main(String[] args) {
          String pat = "[100-200]";
          String input = "100";
          // incpat.replace("[", "\\[");
          // incpat.replace("]", "\\]");
          System.out.println("Pattern" + pat);
          Pattern pattern = Pattern.compile(pat);
          Matcher matcher = pattern.matcher(input);
          if (matcher.matches()) {
               System.out.println("EPC Matched:" + input + " and pattern:"              +matcher.pattern());
}and tested it for different values of input , it's not working. I tried even giving escape characters for "[" and "]" (commented code). Can i use pattern matching in this case.
Please help me.
Regards,
Prashanth

I am facing problem in using a pattern like[200-300] to match any number in
the range 200 and 300 inclusive.Try this one: "(2\d\d)|(300)".
kind regards,
Jos
ps. Waiting for Sabre to jump in telling me that the
parentheses aren't needed ;-)The parentheses aren't needed Jos! :-)

Use of edge detection in pattern matching algorithm?

Hello all,
I work for a group at Texas A&M University researching two-phase flow in reactors. We have been using IMAQ Vision and had a question regarding the use of edge detection in the pattern matching algorithm. I had seen the webcast entitled “Algorithms that Learn: The Sum and Substance of Pattern Matching and OCR” (http://zone.ni.com/wv/app/doc/p/id/wv-705) and in the webcast it was mentioned that the pattern matching algorithm uses edge detection to, (as best I can tell), reduce the candidate list further and to perform subpixel location calculations. However, I was wondering if this edge detection process is still performed if we do not use the subpixel location calculation (i.e. if we uncheck the “Subpixel Accuracy” check box)? Also, if edge detection is performed in the pattern matching algorithm is it consistent with the method described in Chapter 13 of the Vison Concepts Manual (“Geometric Matching”)? Finally, if edge detection is performed in a manner consistent with Chapter 13 of the manual, how does the geometric matching correlation number affect the correlation calculation that was performed in the previous steps? Are they simply multiplied together?
Many thanks!
-Aaron

Jeff,
We are using Imaq Vision Builder 4, with the included pattern matching that can be accessed via the menus (i.e. we haven't created a custom VI or anything.) We are using the software to locate bubbles during boiling experiments and want a deeper understanding of what is going on "behind the scenes" of the algorithm, as we may have to explain how it works later. We have been able to determine most of what we need from the webcast I had previously mentioned, except for the use of edge detection in the pattern matching algorithm.
At the scales involved in our experiments, subpixel accuracy is really not needed and therefore we do not use it. If edge detection is used in the pattern matching algorithm only to determine location with subpixel accuracy, then we do not really need to know how it works because we do not use that calculation. Inversely, of course, if edge detection is used during pattern matching even without enabling subpixel accuracy, then we would like to have a fairly good understanding of the process.
I've read most of the section on geometric matching in the Vision Concepts Manual and wondered if the process described there for edge detection (or feature matching) was also used in the basic pattern matching algorithm?
To summarize, if edge detection is not used in the basic pattern matching algorithm without subpixel accuracy, then that is all I need to know. If edge detection is used for pattern matching even without using the subpixel accuracy calculation, then we would like to learn more about how exactly it is used in the pattern matching algorithm.
We would really appreciate any help you could give us... we've been digging around on the NI website for a couple of weeks now trying to fit together all the pieces of the pattern matching puzzle.
Many thanks!
Aaron

Pattern matching in String

Hi,
I want to do pattern matching using String. Here is my requirement.
String file_name = (String)hash.get("DOCNAME"));
file_name = file_name.replace("'","285745@");
So, whereever I have '(apostrophe) I will replace it with pattern "285745@" and then at another jsp where I get this request parameter I do reverse as follows:
String docname = (String)request.getParameter("doc_name").replace("285745@","'");
Now I know replace function is not going to do this. It is just a indicative, for you to know what I want to achieve. which other java function / method i can implement to get the desired result.
thanks,
pp

String file_name = (String)hash.get("DOCNAME"));
file_name = file_name.replace("'","285745@");The problem here is that String.replace() operates only on char arguments, you cannot replace entire substrings with it.
The String.replaceAll() method, on the other hand, operates on regular expressions. In many common cases (those in which the substring you want to find contains no characters with special meaning to the regular expression processor) you can use it exactly as you would String.replace() except that it operates on substrings.
But regular expressions are much more powerful than that. The javadoc for the "Pattern" class has some information on how to use them. There is also a tutorial at http://java.sun.com/docs/books/tutorial/extra/regex/intro.html which you might find helpful.
In the 1.4 edition of Java there is no longer any need to screw around with while loops and StringBuffers. Nearly any text processing operation can be done with regular expressions.

Is it pattern matching the best way to check presence and orientation of components on a pcb board?

Hi, like i ask on the title i need some hint about this. I need to program a simple AOI machine that must inspect a pcb board and find if all the components are correctly placed and oriented. I though to use the pattern matching with a good template of the object to inspect. Can it work?
All kinds of tips that may come to your mind please tell me, because this is the first time i try a task like this. I already have some experience in image manipulation but not in AOI machines.
Francesco.

Hi Francesco,
you can find some useful information here, here and here.
I hope this will help!
Bye,
Licia

USB SNAP + colour pattern matching ( IMAQ)

I am new to LAbView and currently I am working on colour pattern matching with USB snap. My problem is this program keep prompt me on the IMAQ Learn Colour Pattern. I need someone to help me solve that problem.
Another question is 'Are colour pattern matching require us to save and load file before learn a template?'
I am using LabView 7.1 and I would appreciate anyone who help me. Thanks
Message Edited by Chee Hou on 09-16-2009 03:46 AM
Attachments:
Untitled.vi ‏189 KB

Hello Chee Hou,
Have you tried to run the example to do color pattern matching?
From the example, you do need to have a template picture ready when you are using the colour pattern matching.
You need to Learn Colour Pattern and then load the pattern to do color pattern matching.
Hope this helps.
James
- Meadow -
LabVIEW 7.0 - 2011, Vision, RT, FPGA
TestStand 3.0 - 4.5

Pattern Matching problems

Hi people,
I'm having a slight problem with pattern matching. What I need to do is find if my pattern is a given string an return the end index.
Here's my string:
<TD>Some text</TD>
I need to find everything between the 2 anchor tags. (In this case "Some text"). The query string parameters are the only thing that can change.
Here's what I've tried:
Pattern pattern = Pattern.compile("<a href=\"/cgi-bin/dir/program.cgi?PARAM1=[0-9]&PARAM2=[0-9]*\"onmouseover=\"window.status='';return true;\">");
Matcher matcher = pattern.matcher(myString);
if ( matcher.find() ) {
System.out.println(matcher.end());
System.out.println(myString.substring(matcher.end(), myString.toLowerCase().indexOf("</a>",matcher.end())));
}Of course I've tried a lot of other things. I've also googled to try to find some examples but to no avail.
Thanks for any help.

Just change your Patterne. It will work. The '?' character is being considered as a pattern matching character, while you want it as it is. Use \\ before '?' character.
Pattern pattern = Pattern.compile("<a href=\"/cgi-bin/dir/program.cgi\\?PARAM1=[0-9]&PARAM2=[0-9]*\"onmouseover=\"window.status='';return true;\">");
Hope it helps.

Color pattern matching is very slow

Hi
I tried this code creating one vi application.
After the testing with USB webcam I have realized that the color pattern matching is very slow. How to increase the speed and to work smoothly in real time.
Thank you

Hello tiho,
the color pattern matching is not as fast as 8-bit matching, but should still be fast.
For example, I am attaching a VI for color pattern matching where you load the image, create the template and search do the matching.
In my example I tried color pattern matching on color image of size 4288x2848 pixels and the matching is performed in ~140 ms (~7Hz). So, for a smaller image, I think the real-time processing is quite achievable (I consider real-time 20 Hz or more). The only problem is the template learning, which in my case takes around 10 seconds. But you should learn the template only once in the initialization stage.
Best regards,
K
https://decibel.ni.com/content/blogs/kl3m3n
"Kudos: Users may give one another Kudos on the forums for posts that they found particularly helpful or insightful."
Attachments:
color matching.zip ‏49 KB

Pattern matching help

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