java - Only capture digits instead of the other text in input for a regex like below -

currently regular expression:

^(?:\\s+\\s+)*?(\\s+)\\s+(?:no\\.\\s+)?(\\s+)(?:\\s+\\(.*?\\))?$

captures 418—final in group number 2 input like:

string text="h.b. 418&mdash;final version";

how change regular expression capture number (digits) of "418" in group2 ? edit:

i'd still capture "h.b." in preceding group.

just change boundaries of second group include digits. save "h.b." part, add paranthesis around part too:

^(?:(\\s+)\\s+)*?(\\d+)\\s+\\s+(?:no\\.\\s+)?(\\s+)(?:\\s+\\(.*?\\))?$

IO