如何在python中修复索引超出范围

Question

I have to extract two columns from a website. I know how to read the rows and print them but I'm having trouble extracting only the first and third column, every time I try to attach a variable to a row and try printing the variable it gives me an Error but if I use print(row[2]) it works but at the end it would say index out of range. I don't understand why? Here is what I did:

import urllib.request
import csv

with urllib.request.urlopen("http://archive.ics.uci.edu/ml/machine-learning-databases/iris/iris.data") as webpage:
    reader = csv.reader(webpage.read().decode('utf-8').splitlines())
    for row in reader:

        cor = row[0]
        cors = row[2]
    print(cors)

Answer 1

At the very end of the data set there is an empty row which is being stored as an empty list.

You can check for this by using the following condition:

import urllib.request
import csv

with urllib.request.urlopen("http://archive.ics.uci.edu/ml/machine-learning-databases/iris/iris.data") as webpage:
    reader = csv.reader(webpage.read().decode('utf-8').splitlines())
    for row in reader:
        if not row:
           continue   
        cor = row[0]
        cors = row[2]
    print(cors)

Answer 2

My attempt

import urllib
import csv

webpage =urllib.urlopen("http://archive.ics.uci.edu/ml/machine-learning-databases/iris/iris.data")
reader = csv.reader(webpage.read().decode('utf-8').splitlines())
for row in reader:
    if row:
        cor = row[0]
        cors = row[2]
        print cor,cors