Can someone tell me what functions should i use?

Question

You have different student records containing id of a student and the marks list in each subject where different students have taken different number of subjects. All these records are in hard copy. You want to enter all the data in computer and want to compute the average marks of each student and display

Answer 1

Can you show first your attempt as a link to Sololearn Playground?

Answer 2

Petr Timofeev ,

please also provide samples of input data, and how the output should looks like.