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Jul 13th, 2003
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Java's String Tokenizer

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Hi. I have just been introduced to string tokenizer in one of the java lessons. It can remove characters from an array of strings. So, I am wondering if it could remove a string from an array of string. For example: "the fish was eaten by the cat". I'd like to remove "the" from this array of string, resulting to: "fish was eaten by cat", without getting all t's, h's and e's from the array of string. Is this possible? :roll:
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Posting Whiz
red_evolve is offline Offline
313 posts
since Jun 2003
Jul 14th, 2003
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Re: Java's String Tokenizer

AFAIK, the StringTokenizer does not in itself remove characters; it breaks up a string in tokens at given delimeters. If StringTokenizer is constructed like this:

StringTokenizer st=new StringTokenizer("the fish was eaten by the cat");

...the default delimeters are:
- space character
- the tab character
- newline character
- carriage-return character
- form-feed character

If you want to remove the 'the' from your string, then the above construction would work, since the sentence consists of space characters that delimits each word.

And one way to remove the 'the' from the string, is using a simple little loop to check if the word, a token, is equals to 'the' or not.

Like such:

Create a new output string
Construct the StringTokenizer with the string that is to be parsed ("the fish was eaten by the cat")

Check each word with a loop:
While there is more tokens
Create a new temporary string with the nextToken()
If the temporary string does not equals 'the'
Add temporary string to the output string
(else do nothing)
print out the outputstring

...That should result in: "fish was eaten by cat"

Hope this is of any help,
/Soo-Im
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sooim3 is offline Offline
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since Jun 2003
Jul 14th, 2003
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Re: Java's String Tokenizer

The String tokenizer doesn't have a method to remove tokens. If you have a string like "the fish was eaten by the cat" rather than going through the overhead of creating more objects, just use the native method "replace" or "replaceall" that comes with the String object. You can replace the "the" with an empty string and thus take it out.
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samaru is offline Offline
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since Feb 2002
Jul 14th, 2003
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Re: Java's String Tokenizer

Thank you so much...So, here I am, trying with those suggestions given...

Java Syntax (Toggle Plain Text)
  1. class extra{
  2. public static void main(String[] args){
  3. String output = "";
  4. for(int i=0; i<args.length; i++){
  5. if(args[i] != "the")
  6. output+= args[i];
  7. }
  8. System.out.println("Results: "+output);
  9. System.exit(0);
  10. }
  11. }

I thought the above might work, without using StringTokenizer....but, hmph...it turned out to print the whole thing!
I have tried using sooim3's suggestion, but it didnt work as well, maybe my code is wrong...
I'm not sure...
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Posting Whiz
red_evolve is offline Offline
313 posts
since Jun 2003
Jul 14th, 2003
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Re: Java's String Tokenizer

Uhm, my suggestion wasn't at all as good as the one that followed... you could try this:

public class TokenTest {

public static void main(String[] args) {
System.out.println("the fish was eaten by the cat".replaceAll("the", ""));
}
}

/Soo-Im
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sooim3 is offline Offline
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since Jun 2003
Jul 14th, 2003
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Re: Java's String Tokenizer

Cool~
Thanks...hehe...guess I've learned something new here. Btw, this means that replaceAll is a method in java.lang.String?
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Posting Whiz
red_evolve is offline Offline
313 posts
since Jun 2003
Jul 14th, 2003
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Re: Java's String Tokenizer

Yes. Check out the Java API docs for String:
http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html

The whole J2SE API:
http://java.sun.com/j2se/1.4.2/docs/api/
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a.k.a inscissor
samaru is offline Offline
1,227 posts
since Feb 2002
Jul 16th, 2003
0

Re: Java's String Tokenizer

This code will work if you use
Java Syntax (Toggle Plain Text)
  1. !args[i].equals("the")
instead of
Java Syntax (Toggle Plain Text)
  1. args[i] != "the"
. The latter doesn't work because you end up comparing the location in memory rather than the contents of the memory, like when you compare pointers in C without dereferencing them. Sometimes it will work, but usually it will not.

Quote originally posted by red_evolve ...

Java Syntax (Toggle Plain Text)
  1. class extra{
  2. public static void main(String[] args){
  3. String output = "";
  4. for(int i=0; i<args.length; i++){
  5. if(args[i] != "the")
  6. output+= args[i];
  7. }
  8. System.out.println("Results: "+output);
  9. System.exit(0);
  10. }
  11. }
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Newbie Poster
lohengrin332 is offline Offline
4 posts
since Jul 2003
Jul 16th, 2003
0

Re: Java's String Tokenizer

wow! thanks so much!
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Posting Whiz
red_evolve is offline Offline
313 posts
since Jun 2003
Mar 17th, 2005
0

Re: Java's String Tokenizer

Well i wasn't sure where to post my question but since you guys are talking about tokens and all that, i have a question...

this is my first Java course and i am having troubles doing one of the assignments... well i am suppose to read a file containing grades of students...here is an example

034-23-8901 45 78 85 34
342-67-1231 98 45 67 45
452-57-2351 49 78 61 52

the first 9 digits are the social security of the student and the other numbers are the grades. well i am suppose to open this file ( it is named Grades.txt) somehow i am suppose to read the grades and find the average if the student has an average of 90 or above he will be excluded from the final and then my program has to write an outFile named Exemption... it seems very easy but i just can't get it to work...

My question is do i have to use the tokenizer to separate the numbers... if it is possible how can i do it?

Please i will appreciate any help...
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mackverick is offline Offline
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since Mar 2005

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.
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