In string comparisons

Hello,
I'm new to java and was wondering how I could do an in-string comparison. I.E. check if the string "the" is in "here is the". In ASP you can write inStr(string 1, string2) and I was wondering what the JSP equivalent was.
any help is appreciated!
thanks,
rob

use---> s.indexOf("the");
where s is your " here is the ". create it like this
String s = new String("here is the ") l
or
String s = "here is the";
the method return the index of first occurence of the string "the"
if the index >=0 then "the" is present in your string s.
there is no special method in JSP. U have to use java obejcts and methods only.

Similar Messages

[svn:bz-trunk] 18053: BLZ-571: Use of wrong operator in string comparison in flex.messaging.VersionInfo. java

Revision: 18053
Revision: 18053
Author:   [email protected]
Date:     2010-10-07 03:27:37 -0700 (Thu, 07 Oct 2010)
Log Message:
BLZ-571: Use of wrong operator in string comparison in flex.messaging.VersionInfo.java
Updated the code to use the right operator.
Check-in Tests: PASS
QA: Yes
Ticket Links:
    http://bugs.adobe.com/jira/browse/BLZ-571
Modified Paths:
    blazeds/trunk/modules/core/src/flex/messaging/VersionInfo.java

Fault in string comparisons?

Hallo.
I have the following problem. An XML file, encoded in ISO8859-2, should be presented in a table in a browser's window. The file is "one level deep", something like:
<type>animal</type>
<name>cat</name>
<type>insect</type>
<name>ant</name> ...and so on.
The resulted table should be (its heading in bold):
TYPE NAME
animal cat
insect ant
I process the file using methods from 'org.w3c.dom.*' package and store all the strings (having polish national characters) in a table. The table is displayed correctly.
Besides presentation of everything, the user should be able to select only certain rows from the table. To do this, he has input boxes (as many as the colums in the table) and can enter strings into them. These strings serve as filters. For example, after entering 'animal' in the first box only the first row of the table above should be displayed.
Again, everything works fine, but only if the string entered doesn't contain polish characters. If it does - no one row is displayed.
The application is made as a servlet with the XML file stored in the same server.The strings entered in the input boxes are displayed correctly (with polish characters). The caracters seem to be properly encoded (first the browser is set to use ISO8859-2, and, second, I see their values in the browser's address window when they are sent using GET). I tried PUT too - in vain.
The polish characters in the test XML file were checked in hex editor and are surely encoded in ISO8859-2. The encoded type is declared in the files' header.
So my questions are:
1/ What is wrong?
2/ What to do to correct it?
Any suggestion(s) are highly appreciated.
With many thanks in advance,
L. Pankowski
([email protected])

Sorry once more! Maybe the following version will be better?
(By the way: Is it possible to remove improperly posted messages from the thread?)
Regards,
L.P.
//from doGet method; doPost is the same as doGet
   DocumentBuilder builder;
   File f = new File("C:/servlets/test2.xml");
   try
      DocumentBuilderFactory factory
         = DocumentBuilderFactory.newInstance();
       factory.setValidating(true);
       factory.setIgnoringElementContentWhitespace(true);
      builder = factory.newDocumentBuilder();
//Parse the content of the file as an XML document
// and return a new DOM Document object..
   Document doc = builder.parse(f);
   Element root = doc.getDocumentElement();
   NodeList children = root.getChildNodes();
   int elementsNr = children.getLength();
//Getting column names. Get the first one
//and proceed until you find an identical one.
//(there will be no more than 30 columns)
   String[] colNames = new String[30];
   Node first = children.item(0);
     Element firstElement = (Element)first;
     String firstColName = firstElement.getTagName();
     colNames[0] = firstColName;
     int n = 1;
     Node next = children.item(i);
     Element nextElement = (Element)next;
     String nextName = nextElement.getTagName();
     while (nextName != firstColName)
         colNames[n] = nextName;
         n++;
         next = children.item(i);
         nextElement = (Element)next;
         nextName = nextElement.getTagName();
      columnsNr = i;
      rowsNr = (int)elementsNr/columnsNr;
//Array to put the strings that will be displayed
// in the browser's table
      cells = new String[rowsNr][columnsNr];
//Filling the array..
      for (n = 0; n <rowsNr ; n++)
         for (j = 0 ; j <columnsNr; j++)
            Node child = children.item(j+ n*columnsNr);
            Element childElement = (Element)child;
            Text textNode = (Text)childElement.getFirstChild();
            String text = textNode.getData().trim();
            cells[n][j] = text;
//The content sent to the browser..
   response.setContentType("text/html; charset=iso-8859-2");
   PrintWriter out = response.getWriter();
   String title = "Library";
   out.println("<FORM method=\"POST\">");
   String napis = "To select certain rows fill in the fields and press" +
                        "<input type=\"submit\" value=\"Send\">";
   out.println(ServletUtilities.headWithTitle(title) +
                "<BODY BGCOLOR=\"#FDF5E6\">\n" +
                "<H5>" + napis + "</H5>\n");
   out.println("<H5>Empty field means don't care. To clear all the fields press <input type=\"reset\" value=\"Clear\"></H5>");
//Getting elements of the filter..
//The array to store elements of the filter sent from the browser
   String[] filterFields = new String[columnsNr];
//Empty string means: don't check
   for (n = 0; n <columnsNr; n++)
      filterFields[n] = "";
   Enumeration sent = request.getParameterNames();
//Not null fields' counter -
// used to speed up the search of the matching rows (below)
      k = 0;
   while (sent.hasMoreElements())
      String fieldName = (String)sent.nextElement();
      String fieldValue = request.getParameter(fieldName);
      if (fieldValue.length() > 0)
         n = 0;
         while (!fieldName.equals(colNames[n]))
         n++;
         filterFields[n] = fieldValue;
         k++;
//Preparing and sending input fields of the filter..
   String filterBoxes = "";
//Attempts to adjust the lengths of filter fields
// to the resolution of the screen
   String dl = "size=\"" + (int)100/columnsNr + "%\"";
   for (n = 0; n <columnsNr; n++)
      filterBoxes = filterBoxes + "<input name=\"" + colNames[n] + "\"" + dl + "value=\"\">";
   filterBoxes = filterBoxes + "<BR>";
   out.println(filterBoxes);
   out.println("</form>");
//Forming and sending table header..
   String tableHeader = "";
   for (n = 0; n <columnsNr; n++)
      tableHeader = tableHeader + "<TH STYLE=\"width:1%;\">" + colNames[n];
   tableHeader = tableHeader + "</TH>";
   out.println("<TABLE BORDER=1>\n" + "<TR BGCOLOR=\"#FFAD00\">\n" + tableHeader);
//Searching table rows matching the filter fields
// and sending them to the browser..
//n - row o the table being processed; j - column
   for (n = 0; n <rowsNr ; n++)
      j = 0;
      String row = "<TR>";
      boolean matches = true;
      int KCopy = k;
      while ((KCopy > 0) && matches)
      if (filterFields[j] == "")
         row = row + "<TD>" + cells[n][j];
         j++;
//THIS IS WHERE THE STRING COMPARISON TAKES PLACE
      else if ((filterFields[j]).equals(cells[n][j]))
           row = row + "<TD>" + cells[n][j];
           j++;
           KCopy--;
           else matches = false;
      if (matches)
         while (j < columnsNr)
          row = row + "<TD>" + cells[n][j];
          j++;
         out.println(row);
      out.println("<TABLE BORDER=1 ALIGN=\"CENTER\">\n" +
           "<TR BGCOLOR=\"#FFAD00\">\n" + "</BODY></HTML>");
}

String comparison of big integers

I need to compare big numbers in all number systems, but first step is to be able to compare them in decimal number system, which is not working properly,
e.g.
int Comparison = CompareNumbers("510", "228");
if (Comparison == 0)
MessageBox.Show("N1 = N2");
else if (Comparison == 1)
MessageBox.Show("N1 > N2");
else
MessageBox.Show("N1 < N2");
shows "N1 < N2" which is obviously WRONG
please don't care much about GetDigitValue function and the number systems as I am pretty sure this is OK
string Numbers = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private Int16 GetDigitValue(char Digit)
Int16 Value = Convert.ToInt16(Numbers.IndexOf(Char.ToUpper(Digit)));
if (Value == -1)
throw new InvalidNumberSystem();
else return Value;
private int CompareNumbers(string Number1, string Number2)
int I = -1;
Number1 = Number1.TrimStart('0');
Number2 = Number2.TrimStart('0');
if (Number1 == Number2) return 0; else
if (Number1.Length < Number2.Length) return -1; else
if (Number1.Length > Number2.Length) return 1; else
do {
I++;
} while ((I < Number1.Length) && (GetDigitValue(Number1[I]) >= GetDigitValue(Number2[I])));
if (I < Number1.Length - 1)
return -1;
else
return 1;
The error has to be in this code
do {
I++;
} while ((I < Number1.Length) && (GetDigitValue(Number1[I]) >= GetDigitValue(Number2[I])));
if (I < Number1.Length - 1)
return -1;
else
return 1;

I'm not sure what your goal is here or why you think you need BigInteger for this but you are merely reinventing string comparison. You are, after all, passing
strings to CompareNumbers, not integers.
I rewrote your code in a console test bed.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
class Program
static void Main(string[] args)
int Comparison;
Comparison = CompareNumbers("510", "228");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("228", "228");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("228", "510");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("2", "1");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("2", "2");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("1", "2");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("11111111111111111111111111111111111111111111111",
"1111111111111111111111111111111111111111111111");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("11111111111111111111111111111111111111111111111",
"11111111111111111111111111111111111111111111111");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("11111111111111111111111111111111111111111111111",
"111111111111111111111111111111111111111111111111");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("11111111111112111111111111111111111111111111111",
"11111111111111111111111111111111111111111111111");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("11111111111111111111111111111111111111111111111",
"11111111111111111111111111111111111111111111111");
Console.WriteLine(Comparison);
Comparison = CompareNumbers("1111111111111z111111111111111111111111111111111",
"11111111111111111111111111111111111111111111111");
Console.WriteLine(Comparison);
const string Numbers = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static Int16 GetDigitValue(char Digit)
Int16 Value = Convert.ToInt16(Numbers.IndexOf(Char.ToUpper(Digit)));
return Value;
private static int CompareNumbers(string Number1, string Number2)
int i = -1;
Number1 = Number1.TrimStart('0');
Number2 = Number2.TrimStart('0');
if (Number1 == Number2)
return 0;
if (Number1.Length < Number2.Length)
return -1;
if (Number1.Length > Number2.Length)
return 1;
do {
i++;
} while ((i < Number1.Length) && (GetDigitValue(Number1[i]) == GetDigitValue(Number2[i])));
if (i < Number1.Length && (GetDigitValue(Number1[i]) <= GetDigitValue(Number2[i])))
return -1;
else
return 1;

Use Operator == for String Comparison

Hi,
I would like to know more about the impact of using operator == in String Comparison.
From the reference I get, it state this :
"Operator (==) compares two object addresses to see whether it refers to the same object."
I've tested it with 2 codes as below :
Code 1:
          String Pass1 = "cosmo";
          String Pass2 = "cosmo";
if (Pass1==Pass2)
               System.out.println("1&2:same");
          else
               System.out.println("1&2:not same");
Output : 1&2:same
Code 2:
          String Pass3 = new String("cosmo");
          String Pass4 = new String("cosmo");
          if (Pass3==Pass4)
               System.out.println("3&4:same");
          else
               System.out.println("3&4:not same");
Output : 3&4:not same
Can anyone kindly explain why is the result so? If operator == compares the addresses, isn't it that the 1st code should also have the output :"1&2:not same".

Can anyone kindly explain why is the result so?It's an implementation artifact. Strings are pooled internally and because of that any String literal will be represented by exactly one object reference.
Knowledge of this shouldn't be utilized though. It's safer to follow the basic rule: Use == to compare object references and equals to compare object values, such as String literals.

String comparisons in MySQL

I want to allow my PHP search engine to find records
containing characters that are special to MySQL. For example: if
right now I searched for "%", it would return every record in the
table because % is a MySQL wildcard. I want it to return records
that actually contain a % in the specified fields.
Other current unsearchable characters include ! @ # $ & (
...you get the idea.
How can I make all of these characters searchable in a real
MySQL string comparison?

.oO(AngryCloud)
>I just want a search engine that will search for any
given string within the
>specified fields, regardless of the characters in the
string. So if I search
>for $20, I want to see results where "$20", not just
"20", was actually found
>in the field.
That's what LIKE usually does. Its only special chars are the
wildcards
'%' and '_', which have to be escaped if you want to search
for them.
The rest should work fine.
> The concept of this string comparison is such a simple
one, yet MySQL does not
>seem to be very friendly with real string comparisons.
Don't blame it on MySQL, it usually does very well with such
things.
> You would think there would be some kind of PHP function
that would escape
>every character in a string to make the characters
readable to MySQL simply as
>parts of the string, rather than special MySQL
characters.
It would help to post some code and your query that fails.
Did you try
such a search query directly on the MySQL command line?
Micha

Problems with string comparison using

I have a problem using the > and < comparison operators.
When the xsl:if test uses numeric values the comparison works OK. If the
test uses string values it always returns a false result.
The style sheet below shows an example (which should run against any
XML doc with a root element)
Note - the spurious
tags are just for debugging- I write the
output to an HTML page and IE happens to recognise them
even though the rest of the HTML tags are missing !!
<?xml version="1.0" ?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >
<xsl:template match="/">
<xsl:for-each select="*">
Starting numeric test :
<xsl:if test="(1 < 2)">
In Test, ID= <xsl:value-of select="generate-id()"/>
</xsl:if>
Finished numeric test :
Starting alpha test :
<xsl:if test="('a' < 'b')">
In Test, ID= <xsl:value-of select="generate-id()"/>
</xsl:if>
Finished alpha test :
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
null

Having looked at the XPath spec I believe what I am trying to do (compare strings with gt and lt type tests) is not supported. The spec indicates that they can only be used for node sets or numerics. Presumably the processor is attempting to convert the values to numbers but evaluating them both as NaN (not a number). Can someone confirm this.
I find this restriction quite strange, is this a situation where an extension function is required ? If so can someone point me to some (Java) examples.
null

Not case sensitive string comparison

Is there any chance that the coparison function below returns true value?
Attachments:
Capture.PNG ‏2 KB

Please vote for this idea...
Case Insensitive Comparison Mode for String Equality Comparison
Now is the right time to use %^<%Y-%m-%dT%H:%M:%S%3uZ>T
If you don't hate time zones, you're not a real programmer.
"You are what you don't automate"
Inplaceness is synonymous with insidiousness

String comparisons in TreeMap

I need to use a concatenation of two Strings as my key in a TreeMap, storing an ArrayList of items associated with the key. Obviously, if the key is found, I simply append to the ArrayList associated with that key. However, whenever I use a concatenation, a new key is always created, even if the two strings creating the concatenation are the same.
String key = name + storeNum;
I was under the impression that if I was using Strings, then the TreeMap should use the default compareTo() method which should do a comparison on the String itself, not the memory address, so why would creating the key from a concatenation make any difference? Would creating my own Comparator even help in this situation?

Hi,
String object is an immutable. If you concatenat 2 strings you will always receive new String object. In other words you cannot change String, once created it.
There is mutable "brother" of String - StringBuffer.
I did not exactly undertand what is your problem, but, hopefully, it helps.

Doubt about string comparison

Hi,
This may sound the simplest and the most stupid question to most of u reading it. But still share your knowledge.
Let say we have four Strings defined as
String s = "something";
String s1 = "something";
String t = new String("something");
String t1 = new String("something");
now if I compare this strings using '==' operator, This is what happens.
System.out.println(s==s1); // answer is true
System.out.println(t==t1); // answer is false
Why the 1st SOP returns true if java does not treat strings as primitive and creates objects for every string eventhough it is instantiated with literals?

The answer is:
Java does a String pooling...
why it give true, for the first case is
s == s1
because all this refers to the value in the String pool.. t and t1 are separate Objects although they have the same value("something"). So... when you do t == t1 you check if t and t1 are refering to the same Object(reference comparison), and since they are referencing 2 distinct Objects, the comparison gives false.
Cheers !

Help me explain this String Comparison Bug!

<%
      String strGender = rs.getString("gender");
      if(strGender.equals("male"))
           out.println("1");
      if(rs.getString("gender").equals("male"))
               out.println("2");
      %>In theory, the output should be "12". But guess what, only "2" was printed. I spent hours of debugging because I was supposed to use strGender.equals but the results only ended up in frustrations. So I made experiments, and the direct comparison of rs.getString was the result that worked.
Can anyone explain to me why?

You know what is weird...
the strGender already worked without me changing anything. All i did was eat my dinner, returned after 30mins, then it worked.
Not the first time I encountered this problem.

Problems with string comparison and\or If statement

Right now I'm trying to make a program that will look into all of my music folders, and rename the .mp3 files to a format i want, based on the id3 tags. The program so far looks in all of the folders I want it to, but I get stuck when I need to check if the files are .mp3 files or not. Here is my code so far:
package fileRenamer;
import java.io.File;
public class FileRenamer {
public static void main(String[] argv) {
     File artistsFolders = new File("F:/Music (MP3)");
     File[] artists = artistsFolders.listFiles();
     for(int i = 0; i < artists.length; i++){
          if(artists.isFile()) {
               System.out.println(artists[i].getName());
     } else if (artists[i].isDirectory()) {
          System.out.println(artists[i].getName());
          File albumsFolders = new File("F:/Music (MP3)/"+artists[i].getName());
          File[] albums = albumsFolders.listFiles();
          for(int a = 0; a < albums.length; a++){
               if(albums[a].isFile()) {
                    System.out.println("-" + albums[a].getName());
               } else if (albums[a].isDirectory()) {
                    System.out.println("-" + albums[a].getName());
               File songsFolders = new File("F:/Music (MP3)/"+artists[i].getName()+"/"+albums[a].getName());
               File[] songs = songsFolders.listFiles();
               for(int s = 0; s < songs.length; s++){
                    if(songs[s].isFile()) {
                         int dotPos = songs[s].getName().toString().lastIndexOf(".");
                         String extension = songs[s].getName().toString().substring(dotPos);
                         System.out.println(extension);
                         if(extension == ".mp3"){
                              System.out.println("--" + songs[s].getName());
               } else if (songs[s].isDirectory()) {
                         System.out.println("--" + songs[s].getName());
When I test the code, the line System.out.println(extension); prints .mp3 into the console for all of the .mp3 files. Whatever I try, the if(extension == ".mp3") never seems to declare the two equal. If anyone knows what my problem is, I greatly appreciate the advice and help.
Thanks in Advance,
James

Pojo226 wrote:
I just tried that and it worked perfectly. Thanks.You're welcome.

String comparison having single quote

hi
i m comparing a string which already have a single quote like this
var_name=khurram' shehzad
select * from table where name=' var_name ';
plz help me how to do it bcoz its creating probelm
thanks and regards,

Hi,
I hope the below example will help you.
SQL>SELECT 'abc''' FROM DUAL WHERE 'abc''' = 'abc''';
'ABC
abc'
1 row selected.
SQL>
Regards

Fuzzy Logic for string comparison

Hi All
Thanks for taking the time to read the thread.
I was wondering if any of you has come accross an algorithim to compare two different strings (or find patterns or degree of similarity) between these strings - Fuzzy type logic
The reason I ask is because some of our duplicate invoices are created because the poster miss-enters the reference number - e.g. 1234A and 1234B. We would like to report invoices based on the similarity of the reference number.
I have heard of the Fisher Wagner algorithm that calculates the cost of the differences (based on whether a character is added / omitted or changed) and the Perl algorithm - which finds patterns based on the degree of similarity; but not sure how they are implemented in ABAP or where I can find the open source code
Your help is very appreciated.
Thanks,
Mamdouh

There are a few function modules provided by SAP which seem to be for fuzzy searches. ( Look at SE37 ). For classes, again, there are a few: look in table SEOCOMPO with CMPNAME = *FUZZY* to find the classes and methods.
These may give you what you need.

Xml string comparison

Hi All
I have 2 xml strings as shown below. (Each set is in a string)
<set>
<item table_name='tname1' column_name='colname1'>34</item>
<item table_name='tname1' column_name='colname2'>35</item>
<item table_name='tname3' column_name='colname1'>36</item>
<item table_name='tname1' column_name='colname4'>37</item>
<item table_name='tname2' column_name='colname1'>38</item>
<item table_name='tname1' column_name='colname5'>39</item>
</set>
<set>
<item table_name='tname1' column_name='colname1'>34</item>
<item table_name='tname1' column_name='colname2'>36</item>
<item table_name='tname3' column_name='colname1'>38</item>
<item table_name='tname1' column_name='colname4'>mmm</item>
<item table_name='tname2' column_name='colname1'>38</item>
<item table_name='tname1' column_name='colname5'>50</item>
</set>
I have a table with 3 fields:
TableName, ColumnName, Inc_Exc
tname1, column1, I
tname1, column2, E
tname3, column1, I
I need to write to a file that...
The two sets are identical if all fields in the table that has inc_exc flag set to I are same.
In the above example I have to say it is different because tname3 and column name1 has an include flag but has different values.
Please note that the sets would have been similar if tname3 and colname1 has same value. Even though other values may differ.
I do not have to take values for which there in entry in my database table.
Any ideas how to do this....
Code sample is appreciated, however if basic idea is given I can code it myself.
Thanks much
bib

But this is just basic Java programming, nothing XML-related.
if (lastChunk != prevChunk)Don't use == (or !=) to compare the contents of two String objects. Always use the equals() method, otherwise you are just comparing to see if they are (or aren't) the same object. Two different String objects can contain the same contents. In your case:
if (! lastChunk.equals(prevChunk))with the appropriate checks for null, if necessary.

In string comparisons

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