Delimiter woes

Question

In brief, here is my problem. I'm attempting to scan a string for a very large number that will always start after a ";" and end just before a "=" (without the quotes). I thought I might be able to do this with useDelimiter but it seems I'm on the wrong path here. Could anyone point me toward what I need to grab a string from within two certain points.
For reference, the string will look like this:
;################=xxxxxxxxxxxxxxxx?
Where # represents some number
P.S. I cannot use substring because the number in question is of variable length.

Answer 1

prometheuzz wrote:
Encephalopathic wrote:
Of course you an just ignore this advice as someone will come up with some elegant Regex solution in a few minutes, you'll see.Yes, I am predictable!
import java.util.regex.*;
String text = "sometext;12345678987654321=alargenumberineedandalso;123=rathersmall;888ignore";
Matcher m = Pattern.compile("(?<=;)\\d++(?==)").matcher(text);
while(m.find()) System.out.println(m.group());
This works perfectly but I have one question.
Could you explain what the text inside the quotes is doing here:
Pattern.compile("(?<=;)\\d++(?==)")I understand that it's saying
Start at the ;
grab all the numbers
Stop at the =
but I don't understand how that is derived from "(?<=;)\\d++(?==)"
More specifically, I know what the \\d++ does
I don't understand how (?<=;) says start at ; and (?==) says stop at =
If someone could break that down for me, that would be great.