使用csv模块中的writerow从第一个列开始写入列？

Question

I'm new to python and am working on a utility to prepare some data for analysis in R. So far the utility is reading in two csvfiles, parsing urls for TLDs and SLDs, and then writing those to a csv from a transposed list. I then need to copy the other columns other columns of the csv files from "colrdr" directly into the reader as columns 2 - 6. I tried some direct solutions first, just writing from colrdr the same way I wrote from MasterList previously, but that didn't work (It seemed the colrdr columns weren't being written at all.) After reading some more documentation I also tried using append mode when creating the writer object for the appending the copied columns, but that didn't work either.

Here are the relevant portions of the code:

Here is where I parse the data into TLD/SLDs

# Create a List for future frequency distribution
SLDList = list()
TLDList = list()
MasterList = [SLDList, TLDList]
for fl in infiles:
    with open(fl, 'r') as csvin:
        reader = csv.reader (csvin, delimiter = ',')
        reader.next()
        for row in reader:
            SLDList.append(gettld(row[urlcolumn]))
            TLDList.append(psl.get_public_suffix(row[urlcolumn]))
# Create a List of other columns of infiles
    with open(fl, 'r') as csvin:
        reader = csv.reader (csvin, delimiter = ',')
        colrdr.append(zip(*(list(reader))))

Here I'm creating a few lists which I'm using zip to translate into columns, from which I will write in the second part of the code.

Here is the part where I'm writing that I haven't really been able to figure out

with open(outfile, 'wb') as csvout:
    wtr = csv.writer (csvout, delimiter=',',quotechar='|', quoting=csv.QUOTE_MINIMAL)
    for row in zip(*MasterList):
        wtr.writerow(row)
with open(outfile, 'a') as csvout:
    wtr = csv.writer (csvout, delimiter=',',quotechar='|', quoting=csv.QUOTE_MINIMAL)
    for row in colrdr:
        wtr.writerow(row)

The first part of this works fine. The second part does not do what I would think it should do, and unfortunately it won't even overwrite the first two files, it's as if it's just being ignored by the interpreter, and I don't quite understand why.

Any help would be appreciated, thank you!

EDIT: I can't give actual samples, but the input csvfiles are files from different sources that all have the format

URL, Registrar, Host, ASN

The output should be one file which combines all the others and has the format

TLD, SLD, Registrar, Host, ASN

Answer 1

newrows = list()
for fl in infiles:
    with open(fl, 'rb') as csvin:
        reader = csv.reader(csvin, delimiter=',')
        reader.next() # skip header
        for row in reader:
            sld = gettld(row[urlcolumn])
            tld = psl.get_public_suffix(row[urlcolumn])
            newrows.append([sld, tld] + row[1:]) # row[1:] is everything but the first

with open(outfile, 'wb') as csvout:
    wtr = csv.writer(csvout, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL)
    wtr.writerow(["TLD", "SLD", "Registrar", "Host", "ASN"]) # write header
    wtr.writerows(newrows)