About regular expressions in the cakephp framework

About the regular expression framework regular expression in the cakephp framework

The regular expression is: # ^ /(? :(? P [^/] + ))/(? :(? P [^/] + ))(? :/(? P <_ args _> .*))? [/] * $ #

In the routing route of the cakephp framework, we found that the URL address can be resolved to control, action, and parameter passing. the above regular expression is done. However, what is this strange ??

Explanation

Reply to discussion (solution)

Where did I find my PHP app? how can I find it?

Check the python regular expression (? P ?????) Introduction