Problem with a regex

Question

I want a regex that will match:

A type with an ID:

[Image=4b5da003ee133e8368000002]
[Video=679hfpam9v56dh800khfdd32]

With between 0 and n additional options separated with @:

[Image=4b5da003ee133e8368000002@size:small]
[Image=4b5da003ee133e8368000002@size:small@media:true]

I have this so far :

\[[a-zA-Z]*=[a-zA-Z0-9]*[@[a-zA-Z]*:[a-zA-Z]*]*\]

... but it's not matching all the cases.

Answer 1

\[[a-zA-Z]+=[a-zA-Z0-9]{24}(@[a-zA-Z]+:[a-zA-Z]+)*\]
                           ^                    ^

You were enclosing that section with [], which as you are aware, is for a class, you just want a grouping. You should also ensure that the first match has at least one character, and it seems the id block has 24characters always, if this is the case use, {X} to define a repetition of length X.

Answer 2

Shouldn't the additional options be grouped (instead of brackets!) and marked optional (instead of *)? And you should use + instead of * or else an empty string would be matched.

\[[a-zA-Z]+=[a-zA-Z0-9]+(@[a-zA-Z]*:[a-zA-Z]*)*\]