python - Why does this output the first element in the tuple?

Question

I was reading through some answers and this was a solution to printing ['Bill', 'John', 'Tony', 'Phill'] from the list below.

mylist = [('Bill', 1), ('John', 1), ('Tony', 2), ('Phill', 2)]
print([x for x, y in mylist])

What does this line do?

print([x for x, y in mylist])

Answer 1

x,y in mylist[i]

saves the name of a certain tuple in x and the number in y.

for x,y in mylist

cycles through all the tuples in mylist.

print([x for x,y in mylist])

prints the x of every tuple.

print([y for x,y in mylist])

would print all the numbers.

print([z for z in mylist])

would print all the tuples.