Week 1: Sets

In the first week of lecture, I had a difficulty to accept the concept of 'not all' and 'not any' and I couldn't connect the concept of building set and using boolean even though I read the material before the class. Honestly, I didn't understand the lecture right away so I could not write anything on the sheet Professor handed out.

After the lecture, I reviewed what I learned today and try to understand the concept step by step. When I just read the note, it wasn't clear to me what these all 'def's mean. So I decided to use examples on python. I wrote the random sets of S1, S2 in python. I tried given 'def's using True and False as elements in a set. After I tried couple of examples, I could see the big picture and could figure out what the comments could have been in the lecture. Following is the one example:

 def q0(S1, S2):

     ''' (set, set) -> bool

     Return whether ...

     '''

     return not all({x in S2 for x in S1})

It would return 'True' when  all elements in S1 are not in S2.

In other words, def q0 means:

Some elements of S1 is not an elements of S2.

At first, I was not familiar with expressions, however, after reviewing the material thoroughly it did not feel too complicated. As a result, I could solve the first week tutorial problems without having difficulties.