python - ?P<sign>.*中的p是什么意思呢

Question

m = re.match(r'(\w+) (\w+)(?P<sign>.*)', 'hello world!')

这句代码中的?P<sign>.*里的p是什么意思？或者给我一篇博客参考下用法。

Answer 1

Python Regular Expression Guide

Answer 2

Here is another link to learn regular expressions
Introduction to Python crawler seven regular expressions

Answer 3

In fact, it means named group in regular expression. You can think of this P as the abbreviation of the word Pattern