The first two answers give good examples. You can also use "so I do" as a response to someone describing you. For example: "You have a little ketchup on your lip." "So I do! Thanks for telling me" or "You have a rip in your jeans.' " So I do." Hope this helps :)

You can use "So do I" at the end of the question or sentence, "So I do" you can use in the middle of the sentence. You said you know about how did we use "So do I", and one more example for "So I do": I want to improve my English skills, so I do a lot of grammar exercises. these two phrases have a different meaning, I hope you understood it on examples.

so do I , 表相同，表示你会和前者有同样的想法或做法。比如 You like coffee，so do I. (你喜欢咖啡，我也是。表示你和他一样都喜欢咖啡) so I do. 表肯定。 表示你是肯定前者，你就是这样的。 比如 A:I know you like coffee. B: So I do. (A说，我知道你喜欢咖啡。B回答：是的，我喜欢咖啡。 总结一下下：so I do,表示你对前者说的话 的肯定，你就是喜欢咖啡。 而 so do I, 表示你和他一样，都喜欢咖啡） 希望我的回答，对你有用。。。。:)

i'm afraid they've missed the point of your purpose .i'd like to give two expamles: 1.--------- i like jazz. -------- so do i. 2. she advised me to take a chance and so i did. || pay attention to the subjects.

I am weak, so I do exercises to make myself stronger.