Differences between “Oui” and “Si” in the affirmative?

Question

The usual form of yes in French is "oui."But my understanding is that there is another form of the affirmative, "si," (similar to the Spanish). It is used only in limited contexts, and is perhaps a different, "weaker" way of saying "yes."In Japanese, for example, there is a word "hai," which is a "conditional" yes.In what contexts are "si" used, and how does it differ from "oui"?

Answer 1

You don't like ice cream do you? Tu n'aimes pas la glace, n'est-ce pas?

Si je l'aime!!!!

Answer 2

"Si" is such a fun word in French! It does mean yes, but in a very particular context: it is only used when saying yes to a negative question or comment. I believe it differs from the Japanese "hai" in this way, but it is similar to the German "doch."

Examples: Tu n'as pas faim? (You're not hungry?)

Si! J'ai très faim! (Yes! I'm very hungry!)

Il n'a pas 30 ans. (He's not 30).

Si! (Yes, he is!)