Regex, exclude certain character

I am trying to build a regular expression. However I get stuck and can't find the solution :(. Please help.

I want to get the string contains {\d} that are not preceed by \.

Example:

abc{1}def{2} ghi{3} jkl{4}{5}mno \{6}ofg\{7}{8}.

The result would be :

{1} {2} {3} {4} {5} and {8}.

Any 开发者_如何学运维idea to build regex for it?

Thank you

You can use the regex:

(?<!\\)(\{\d\})

(?<!\\){\d}

This will match only the portions you want.

You use a caret after the left square bracket to negate a character class.

I.e. [^\\](\{\d\})