What does the x7f-xff in this regular mean?

See a source code written in the regular
/\<\{\s*\$[a-za-z_ \x7f-xff][a-za-z0-9_ \x7f-\xff]\s*\}\>/i

What do you mean by \x7f-xff in the office?

Reply to discussion (solution)

\x7f-\xff represents ASCII characters from 127 to 255, where \ is escaped.

Why do you want to value this range from 127 to 255? I'm sorry, I'll ask you a little bit further.

echo Bin2Hex (' why '); Get CEAACAB2C3B4

echo "\xce\xaa\xca\xb2\xc3\xb4"; to why

Why do you want to value this range from 127 to 255? I'm sorry, I'll ask you a little bit further.

It could be an IP address category.
A: the first is 0;1.0.0.0~126.0.0.0; host number 24 bit
B: The first two bits are 10;128.1.0.0~191.255.0.0; host number 16 bit
C: The first three bits are 110;192.0.1.0~223.255.255.0; Host number 8 bit
D: The first four bits are 1110;224.0.0.0~239.255.255.255
E: The first four bits are 1111;240.0.0.0~255.255.255.254

！！！ This and IP have what relationship!!!

In brackets, in addition to the brackets themselves or the range of connectors, other cases are not metacharacters. So [\x7f-xff] represents the character groups of \, X, 7, F-x, F, F.

Sorry, yesterday's reply is wrong, correct, the meta-character "\XN" is used to match N, where n is the hexadecimal escape value, which must be a determined two digits long. For example, "\x41" matches "A" and "\x411" is equivalent to "A1". The connector "-" represents a range (if not the beginning) within a character group (a string within the brackets). It is important to note that the provisions on metacharacters are different within and outside the character group.

