Tokenizing with String.split()

[John Paterson]

Hi Folks,

In page 503 of the Kathy Sierra book, there is the following sample code:

import java.util.*;
class SplitTest {
public static void main(String[] args) {
String[] tokens = args[0].split(args[1]);
System.out.println("count " + tokens.length);
for(String s : tokens)
System.out.println(">" + s + "<");
}
}

With this invocation:

java SplitTest "ab5 ccc 45 @" "\d"

It gives the following result:

count 4
>ab<
> ccc <
><
> @<

My question is, how can the count be 4? My understanding is that the value being assigned to the token array should be the number of elements left after the digits are removed. Hope someone can advise. Thank you.

[Henry Wong]

John Paterson wrote:
My question is, how can the count be 4? My understanding is that the value being assigned to the token array should be the number of elements left after the digits are removed. Hope someone can advise. Thank you.

The example actually prints the four elements -- so you know what the application says the four are. How many elements do you think it should there be? And what should the elements be?

Henry

[Sergej Smoljanov]

I also interesting result of:

        String[] tokens = "545".split("\\d");
        System.out.println("count " + tokens.length);
        for (String s : tokens) {
            System.out.println(">" + s + "<");
        }

i expected

count 2
><
><

, but result is

count 0

and

        String[] tokens = "5/45".split("\\d");
        System.out.println("count " + tokens.length);
        for (String s : tokens) {
            System.out.println(">" + s + "<");
        }

expected output:

count 2
>/<
><

but get:

count 2
><
>/<

[Henry Wong]

Sergej Smoljanov wrote:I also interesting result of:

        String[] tokens = "545".split("\\d");
        System.out.println("count " + tokens.length);
        for (String s : tokens) {
            System.out.println(">" + s + "<");
        }

i expected

count 2
><
><

, but result is

count 0

The String split() method uses the one-argument split() method of the Pattern class. See... link

And notice the mention on "trailing empty strings" in the result.

Hope this helps,
Henry