Split string in Java to show only sequence of characters

Question

I am trying to split a string like the string below

3x2y3+5x2w3–8x2w3z4+3-2x2w3+9y–4xw–x2x3+8x2w3z4–4

to a table of strings which does not have any number or sign.

That means

a[0]=x
a[1]=y
a[2]=x
a[3]=w

I tried this

split("(\\+|\\-|\\d)+\\d*")

but it seems that it does not work.

Answer 1

The following should work:

String[] letters = input.split("[-+\\d]+");

Answer 2

Edit: -

If you want xw to be together in your resulting array, then you would need to split your string: -

String[] arr = str.split("[-+\\d]+");

Output: -

[, x, y, x, w, x, w, z, x, w, y, xw, x, x, x, w, z]

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You can replace all the unwanted characters with empty string, and split on empty string.

String str = "3x2y3+5x2w3-8x2w3z4+3-2x2w3+9y-4xw-x2x3+8x2w3z4-4";
str = str.replaceAll("[-+\\d]", "");        
String[] arr = str.split("");       
System.out.println(Arrays.toString(arr));

Note that, this will add an empty string as the first element of your array, which you can handle.

Output: -

[, x, y, x, w, x, w, z, x, w, y, x, w, x, x, x, w, z]

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Note that - sign in your question is different. You should replace it with the one on your keyboard. Currently it is not matching - sign.