Regular Expression

RegEx can be tricky! Hopefully this will provide some help.

This is an example of perl-regex format which is used in Netbeans and Atom

a-c(\d[{2-2}]\d{1}?[{0-9}]\d)

This will match a-c213 as well as a-c2199. It will not match b2199 nor a-c229. Can you figure out why?

The ? makes the following statement optional.

\d is a digit

[{x-y}] indicates a range from x to y. This can be alphanumeric.

{1} indicates that just that character is accepted.

Everything outside the parentheses is literal. So "a-c" matches that string, literally.

If you perform a search/replace, you can use $1 to grab the first match, $2 for the second, etc.

e.g. 
input: What is a word 
search: What is a(.*)
replace: This is not a$1
result: This is not a word

The (.*) above is a wildcard, it'll match any number of anythings, like the space after "a"!