Regular Expression introduction (Microsoft) -- 7. common characters

Common characters
A common character consists of all the print and non-print characters that are not explicitly specified as metacharacters. This includes all uppercase and lowercase letter characters, all numbers, all punctuation marks, and some symbols.
The simplest regular expression is a single normal character that can match the character itself in the searched string. For example, the single-Character Mode 'A' can match the 'A' letter that appears at any position in the searched string '. Here are some examples of Single-character regular expression patterns:
//
/7/
/M/
The equivalent single-character Regular Expression of VBScript is:
""
"7"
"M"
You can combine multiple single characters to obtain a large expression. For example, the following Visual Basic Scripting Edition regular expression is an expression created by combining a single character expression 'A', '7', and 'M.
/A7M/
The equivalent VBScript expression is:
"A7M"
Note that there is no join operator here. All you need to do is place one character after the other.