Just use \1 ... \9 (or $1... $9 在某些正则表达式实现中)，就像您通常会做的那样.编号是从左到右，基于开放括号的位置(因此嵌套组的编号大于嵌套组的编号).

Just use \1 ... \9 (or $1 ... $9 in some regex implementations) like you normally would. The numbering is from left to right, based on the position of the open paren (so a nested group has a higher number than the group(s) it's nested within).