CODEWITHSUNDEEP
pythoncsv
bigTree
bigTree

Reputation: 2173

TypeError with DictReader

I am working on a csv file using DictReader and DictWriter.

I tried to work based on the following code found here:

import csv

fieldnames = ['Node', 'ID', 'Test Description', 'file-name',
              'module', 'view', 'path1','path2'] # defines order in output file

with open('testdata.txt', 'rb') as csvinput:
    with open('testdata2.txt', 'wb') as csvoutput:
        csvwriter = csv.DictWriter(csvoutput, fieldnames, delimiter=',')
        csvwriter.writeheader()
        nodecount = 0
        for row in csv.DictReader(csvinput):
            nodecount +=1
            row['Node'] = 'node %s' % nodecount  # add 'Node' entry to row data
            csvwriter.writerow(row)

I am using python 3.2 and I get the following error:

  File "/usr/lib/python3.2/csv.py", line 153, in writerow
  return self.writer.writerow(self._dict_to_list(rowdict))
TypeError: 'str' does not support the buffer interface

I read that this error could be due to the fact that "If you use Python3x then string is not the same type as for Python 2.x, you must cast it to bytes (encode it)."

But here, the files are already opened using the 'b' argument (and therefore as binary files) right?

Upvotes: 2

Views: 838

Answers (1)

DSM
DSM

Reputation: 353209

You're using a Python 2 example for the csv module in Python 3. As you guessed, as part of the str/bytes switch, the required pattern for opening files for the csv module changed a little bit. (I admit the difference can be a headache, but things make so much more sense in Python 3 than Python 2 that it was worth it.)

As the documentation explains, the new required idiom for opening csv files for reading/writing is

with open('testdata.txt', newline='') as csvinput:
    with open('testdata2.txt', 'w', newline='') as csvoutput:

Upvotes: 5

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