Regexp for special string

I need a regexp 开发者_Go百科which matches to the sting which

• starts with $
• ends with $
• contains some alphabetical characters (not defined how many)

e.g.

$ABC$    # ok
$ABCDEF$ # ok
$ABC     # not ok
AC$      # not ok

This is the regex you want:

/^\$[a-z]+\$$/i

Components explained:

1. ^ - Start matches only from the beginning of the input
2. \$ - Match a literal $ (the \ is used for escaping special chars)
3. [a-z] - Match any of the letters (combined with the i modifier at the end matches both lowercase and uppercase)
4. + - match items from the preceding character class 1 or more times
5. \$ - See 2
6. $ - End matches only at the end of the input
7. / - Is the standard delimited for regex, but it may vary in some languages
8. i - Placed at the end is the Case Insensitive modifier

Good reading: http://www.regular-expressions.info/

^\$[A-Za-z]*\$$

This will match 0 or more characters in between dollar signs. If you want to match one or more, use ^\$[A-Za-z]+\$$.

This could probably be written with fewer characters, but I have no indication of what regex engine you're using, so I can't use any specific features.

Something like

^\$[a-zA-Z]+\$$

should work. Syntax depends on where do you use it