Python: How would one represent this particular for loop using list comprehension?

Question

As the title states, I would like to know how to use "list comprehension" to shorten this for loop. The loop is functional; however, the details of the assignment given to me states that I should have at least one list comprehension and this was the only for loop in my code. By the way, I am fairly new to python.

z=0
for elements in a
    if a[z] in c:
        z=z+1
    elif a[z] in b:
        c.append(a[z])
        z=z+1
    else:
        z=z+1

Also, if there are any general tips to shorten this, that would be much appreciated.

Answer 1

I assume what you want is to take elements from a and place them in c if those elements are present in b . Also you want to make sure that only one such element exits in c , meaning c is a set.

You can do that as

>>> a = [1, 3, 5, 7, 3]
>>> b = [3, 5]
>>> set([ i for i in a if i in b ])
set([3, 5])