i need to make a regex that matches either a or c on the first slot, "the char(0)" but i only know how to use from A-Z
string.matches(("^[A-C]{3}$")) //this includes B, i dont want this to happen
Can i add a string? or a char variable? insteas of the a and c? like
"[+ char +]"
?
When you use - in a character class expression, you allow the first character, the last character, and everything in between. Hence, A-C means 'A', 'B', or 'C'. If you want either 'A' or 'C', use [AC] instead:
string.matches(("^[AC]{3}$"))
Can I add a
Stringor acharvariable?
Yes, if you obey the general rules of character class expressions:
- or a ^ in your String, put them at the back] or \ characters in your String, add an escape character in front of them.Assuming that there are no special characters in your string, you can do
String str = "ac";
string.matches(("^[" + str + "]{3}$"))
try "^[AC]{3}$"
The brackets match only a single character, so in this case they will match only A or C
First you should have done some research in the internet: http://www.vogella.com/tutorials/JavaRegularExpressions/article.html . This will give you very good tutorial on regex.
According to that link you should try:
string.matches(("^[AC]{3}$"))
Hope that helps
^[ac]is a regex that matches a or c as the first character of the string. But you don't need a regex to do this.