What is the regex for this the pattern "--> xxx"

Issue

"--> xxx", where xxx is a digit

example:

--> 200
--> 201
--> 403

I want to check if a string begins with that pattern

My attempt:

message.contains(Regex("-->\\s+(\\d+)"))

Solution

In Java String you'd use the regex you have plus ".*" to match other characters after digits with matches(regex):

message.matches("-->\\s+(\\d+).*")

So these are all true:

"--> 200 xyz".matches("-->\\s+(\\d+).*")
"--> 403".matches("-->\\s+(\\d+).*")

If repeating this often you may be better off creating a Pattern and Matcher once before resetting the matcher instance each time for a string to check:

Pattern p = Pattern.compile("-->\\s+(\\d+).*");
Matcher m = p.matcher("");

// Following are all true, showing string starts with "--> NNN":
m.reset("--> 200 abc").matches();
m.reset("--> 403 xyz").matches();

Answered By - DuncG