Cut .csv to pieces and save as .csv

[merlem]

when trying to run your code from above I get:


csvwriter.writerow([line[0], line[columnumber]])

TypeError: a bytes-like object is required, not 'str'

That's strange. For me, the code runs without this error. I'm not sure whether that's relevant in this case, but I am using python in the version 2.7. If you have version 3, that can cause incompatibilities.
And I have to confess that I don't understand this message... the expression in the brackets should be a list, not a string. But 'a bytes-like object', I'm not sure what is included in that and what isn't.
Maybe somone else can help there?

According to the code: you may try to replace the old 'firstlinedone'-part with:

        for columnumber, column in enumerate(line):
            newfilename = "test" + str(column) + "a.csv"
            if newfilename in listoffilenames:
                newfilename = "test" + str(column) + "b.csv"
                listoffilenames.append(newfilename)
            else:
                listoffilenames.append(newfilename)
            newfile = open(newfilename, 'wb')
            listoffiles.append(newfile)
            firstlinedone = True

Any ideas on how to approach getting better at this?

Not really, except maybe: try to get stuff done that you need for something else. It keeps up motivation   . But learning programming remains hard and difficult for a long time. Don't give up too easily!