t.split(".") returns ArrayIndexOutOfBounds exception.

[aswolff]

I have a file of strings similar to:
AC00.1
AC00.2
AC11.3

I am using the following code:

String[] MyPrg = new String[2];

while ((t = in.readline()) != null) {
MyPrg = t.split(".");
System.out.println(MyPrg[0].toString());
}

I get error on first entry:
AC00.1
EXCEPTION: java.lang.ArrayIndexOutOfBoundsException: 0
java.lang.ArrayIndexOutOfBoundsException: 0
at Role2Tkn.main(Role2Tkn.java:224)

I would expect :
MyPrg[0] to contain AC00
and
MyPrg[1] to contain 1

What am I overlooking here?

Thanks for any help!!!

 

[feherke]

Hi

String[] MyPrg;   [gray]// no need to initialize it, but no error[/gray]

while ((t = in.readline()) != null) {
  MyPrg = t.split("\\.");   [gray]// period ( . ) is metacharacter, escape it[/gray]
  System.out.println(MyPrg[0].toString());
}

http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/Pattern.html

http://regular-expressions.info/

Feherke.

http://rootshell.be/~feherke/

 

[Diancecht]

Appart from that, you don't need the toString clause, it's already a String array.

Cheers,
Dian

 

[aswolff]

Hmmm...I guess its a bug in Eclipse that led me astray. I tried escpaing it and receiving a eclipse warning saying that this character did not need to be escaped.


I'll try out your suggestion. Thanks!

 

[stefanwagner]

Perhaps you used just one backslash.
You need two - one to mask the dot, but since the backslash is used for escaping on the file-level, you have to escape it too.
\n is a newline
\t is a tab
\. is bogus, because a dot doesn't need to be escaped.
\\. is backslash + dot.

seeking a job as java-programmer in Berlin:

http://home.arcor.de/hirnstrom/bewerbung

 

[Diancecht]

So for those like me that don't understando regular expresions, do we need to use "." or "\." to split?

I guess the problem comes because t hasn't what's suppose to have. I'd print t and chech the size of the splitted array before printing the results.

Cheers,
Dian

 

[Diancecht]

Oh, and I seriously doubt it's an Eclipse bug. If Eclipse and you disagree, I bet you're wrong.

Cheers,
Dian

 

[feherke]

Hi

So for those like me that don't understando regular expresions, do we need to use "." or "\." to split?

The period ( . ) in regular expressions means any character. But while aswolff wants to split on the literal period character, not on any character, must escape the period.

( In some languages with slightly different regular expression handling [tt]"AC00.1".split(".").length[/tt] would be 6. )

Feherke.

http://rootshell.be/~feherke/