emacs regexp-builder doesn't work in replace-regexp

Question

I have an emacs buffer containing the text

a1b2c3

using the regexp-builder, i create the regexp

\"b\\\\(2\\\\)\"

Answer 1

regexp-builder can show the regexp in several syntaxes. By default, it uses the syntax that is appropriate to put in an Emacs Lisp source (read syntax), so the regexp is placed between double quotes and every backslash is doubled. For interactive use, select the string syntax with C-c C-i (reb-change-syntax).