Generally, you are expected to attend class unless you have notified your instructor by email and have an excuse that fits into one of these categories:
If you are working on a project with a partner (paired programming labs) or a team (project-based learning), you should also inform your partner or team and arrange to work outside of class in order to meet the deadline.
I am very sorry, but other types of absences are not excused and will not be accepted as a reason to request an extension. While I sympathize with a desire to attend family events or participate in major milestones of friends, such as weddings, I cannot extend deadlines in these cases.
Whether or an absence is excused or not, you are still responsible for completing the readings and labwork for that day. Being gone from class does not mean that you will not be expected to learn the material and complete homework on time, with reasonable accomodations for excused absences. You should get notes from classmates and review the lecture slides posted for that day. If you are struggling to understand missed material, attend mentor or tutor sessions or request an individual tutor to help you.