URL正規表現comprension

Question

私はPHPで使用するこの正規表現を理解しようとしていますが、私はnoobyですので、私にとっては非常に難しいです。この正規表現は何をしてくれますか？

/(?:https?:\/\/)?(?:[a-zA-Z0-9.-]+?\.(?:[a-zA-Z])|\d+\.\d+\.\d+\.\d+)/

ありがとうございました！

より多くの情報ビューについては

Answer 1

Brackets 

[0-9] - It matches any decimal digit from 0 through 9. 
[a-z] - It matches any character from lower-case a through lowercase z. 
[A-Z] - It matches any character from uppercase A through uppercase Z. 
[a-Z] - It matches any character from lowercase a through uppercase Z. 

Quantifiers 

p+ - It matches any string containing at least one p. 
p* - It matches any string containing zero or more p's.  
p? - It matches any string containing zero or one p's. 
p{N} - It matches any string containing a sequence of N p's  
p{2,3} - It matches any string containing a sequence of two or three p's. 
p{2, } - It matches any string containing a sequence of at least two p's. 
p$ - It matches any string with p at the end of it. 
^p - It matches any string with p at the beginning of it. 

Expression & Description 

[[:alpha:]] - It matches any string containing alphabetic characters aA through zZ. 
[[:digit:]] - It matches any string containing numerical digits 0 through 9. 
[[:alnum:]] - It matches any string containing alphanumeric characters aA through zZ and 0 through 9. 
[[:space:]] - It matches any string containing a space. 

：Regex