Preg_match: Regular Expression used to determine the user name

Problem
Judge the regular expression of the user name
Solution
Preg_match ('/^ \ s * $ | ^ c: \ con $ | [%, \ * \ "\ s \ t \ <\> \ & '\]/', $ username)


How Can I copy the code?

Thank you!

Copy the PHP content to the clipboard. PHP code: [%, * "\ s \ t \ <\> \ & '\]


This part can be basically understood, *, double quotation marks, space characters, tabs, less than, greater than, &, single quotation marks, but why use two backlash?

What do we mean by the last four backslash lines?

[]


Reference answer
[Img] http://www.111cn.cn/bbs/images/smilies/default/funk.gif#/img]
Reference answer
The user name is prohibited from being signed. Blank characters and line breaks.

It seems that the regular expression author is a little abnormal.
Reference answer
I don't know much.
^ \ S * $ | ^ c :.
^
Why use two \ s?
C:
What does it mean?
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/^

The most strange thing is here. ^ put it in the middle of the expression. I really don't think of what it means ..
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\ S *

Why should we use two \
This is a single quotation mark. Simply say one is enough.
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Du Jiang's book has said that \ s \ t \ r all have...
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Can't you answer this question in front of me? [img] http://www.111cn.cn/bbs/images/smilies/default/42.gif#/img]
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\ Con what is this?
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Can you tell me what you know?