Question

Suppose I have a function like this:

def getNeighbors(vertex)

which returns a list of vertices that are neighbors of the given vertex. Now I want to create a list with all the neighbors of the neighbors. I do that like this:

listOfNeighborsNeighbors = []
for neighborVertex in getNeighbors(vertex):
    listOfNeighborsNeighbors.append(getNeighbors(neighborsVertex))

Is there a more pythonic way to do that?

Answer 1

[x for n in getNeighbors(vertex) for x in getNeighbors(n)]

or

sum(getNeighbors(n) for n in getNeighbors(vertex), [])