Question about split()

[kraigballa]

How come when I pass a String that looks like this:
(6 + 2) + 2

When I use the split method the first index in tokens has nothing, and then the second index has "("? The first index should have "(" not nothing. Isn't that was trim() does?

String[] tokens = infix.trim().split("");

[ozzyman]

String.split allows you to specify a delimiter to split the String by.

Try something like this instead:

String s = "split-this-string";
String[] sArr = s.split("-");

String.trim() simply removes leading and trailing whitespace from the String.

You can find out more about String methods by looking at the String java doc:
String (Java 2 Platform SE v1.4.2)

[kraigballa]

If I have a string that is like this:

String str = "(6 + 2) + 2";

How can I get an array that looks like this..?
{ "(", "6", "+", "2", ")", "+", "2" };
Notice spaces have been taken out as well.

[ozzyman]

trim() wont help you here

Use String.replace(" ", "") to replace white space with nothing

Then use String.toCharArray() to return a char[] array which will contain each char in a separate array element of course.
(This is because in Java, String is really a wrapper for a char[] array)

As I said before, read the java docs to see what you can do.

Click the link I left above, scroll down to the Methods section. It tells you a description of each method so you'll know next time how you can do certain tasks.

[kraigballa]

It doesn't makes sense that when I do this...

String tokens = infix.trim();
    	tokens = infix.replace(" ", "");
    	String [] token = tokens.split("");

My array looks like this:
{ " ", "(", "6", "+", "2", ")", "+", "2" };

Or at least it is nothing in the first index...

[wsaryada]

It's like splitting an empty string, so as the result is the original string, an empty string. That is if you have a code like:

String[] split = "".split("");

The split array length will be 1. And it contain an empty string.

[eRaaaa]

It doesn't makes sense that when I do this...

String tokens = infix.trim();
    	tokens = infix.replace(" ", "");
    	String [] token = tokens.split("");

My array looks like this:
{ " ", "(", "6", "+", "2", ")", "+", "2" };

Or at least it is nothing in the first index...

You should read whats posted by ozzyman
infix.replace(" ", "") --> your string is "(6+2)+2".
If you would use toCharArray, you would get an array of characters { '(', '6', '+', '2', ')', '+', '2' } - is that not enough? :D
If you really want to use split and want to have some strings like "6","+" ... try this:
String[] token = tokens.replace(" ", "").split("(?<=.)");