filter list of tuples by certain axis

I have a csv file with 3 columns of x,y,z coordinates, i.e. this format:

I used the code below, to import it and process its data:

import csv
from operator import itemgetter

csvfile = open(r'C:\Users\%username%\Desktop\Deep-lizard\x_y_z coor.csv')

inFile = csv.reader(csvfile)
# skip header
inFile.__next__()

#Read and sort the vertices coordinates (sort by x and y)
vertices = sorted( [(float(r[0]), float(r[1]), float(r[2])) for r in inFile], key = itemgetter(0,1) )

This turns vertices into a list of tuples:

What I want to achieve is filter the list so that, if the third element in the tuple (i.e. the z coordinate) is bigger than 0, then include that entry (the tuple of 3 elements) in the list otherwise if it's 0 then don't include it. What's the best way of doing this?