python - Copy list and append an element in one line

Question

Can this be reduced to a single line (after assigning a)?

a = [1,2,3]
b = a[:]
b.append(4)

Answer 1

The following is probably the simplest:

b = a + [4]

Here, you don't need a[:] since we're no longer copying the reference (+ creates and returns a new list anyway).