Question

So I’m reading a CSV file with two columns, and then taking the product of all of them.

What I am trying to do is convert t his product from a list of tuples, to a list of lists. I ultimately want to combine each tuple into a string with a comma. Here’s my code:

rowa = []
rowb = []

for row in csvfile:
    if row[0] != "":
        rowa.append(row[0])
    if row[1] != "":
        rowb.append(row[1])
wordlist = list(product(rowa, rowb))

And my pseudocode is this:

for x in wordlist:
    x = list(x)
    x.join(" ")

print wordlist should bring up a list of strings, which will be the old tuples, turned into a list and then joined together with a space

Answer 1

The join method works the other way around; call it on the space string:

for x in wordlist:
    " ".join(x)

It works on any sequence, so there is no need to convert tuples to lists here.

Note that you can dispense with the != "" tests for your columns; the empty string is considered boolean False as well:

for row in csvfile:
    if row[0]:
        rowa.append(row[0])
    if row[1]:
        rowb.append(row[1])

Finally, because you are already iterating over the wordlist, just leave it a generator and dispense with the list call altogether.

wordlist = [" ".join(x) for x in product(rowa, rowb)]