PHP：我不明白为什么此正则表达式与此表达式不匹配

Question

I would like to understand what this regex correspond to:

preg_match("/\/[A-z]{2}\/[^\/]*/", "expression_to_test")

I've tried with /a2/ but it does not match. As I understand the regex, in this order we have: "/" which is a delimiter, "/" stands for backslash, [Az]{2} stands for 2 letters, then another "/" then no "/" multiple times...

So, it's obviously not the good answer, if you find a matching pattern I would be great.

Thanks

Answer 1

a2 wont match az cause you have decimal number in there. Try this:

\/[A-Za-z0-9]{2}\/[^\/]*

https://regex101.com/r/iWSrPD/1

Answer 2

A-z a single character in the range between A (ASCII 65) and z (ASCII 122) (case sensitive)

2 does not fall in it and so it fails.(as ascii for 2 is 50 )

/Ab/ matches.

See demo.

https://regex101.com/r/woJSXd/1

See in table. Only from 65 to 122

You need to use [A-Za-z] as [Az] can match much more than intended.See table.