unicode方法在Python3中不起作用

Question

def unicode_csv_reader(utf8_data, dialect=csv.excel, **kwargs):
    csv_reader = csv.reader(utf8_data, dialect=dialect, **kwargs)
    for row in csv_reader:
        yield [unicode(cell, 'utf-8') for cell in row]

filename = '/Users/congminmin/Downloads/kg-temp.csv'
reader = unicode_csv_reader(open(filename))

out_filename = '/Users/congminmin/Downloads/kg-temp.out'
#writer = open(out_filename, "w", "utf-8")
for question, answer in reader:
  print(question+ " " + json.loads(answer)[0]['content'])
  #writer.write(question + " " + answer)

reader.close();

This code works in Python 2.7. But it gives an error message in Python 3.6:

Unresolved reference 'unicode'

How to adapt it to Python 3.6?

Answer 1

Simply ensure your data is str , not a bytestring, to begin with, and just use csv.reader without this decoding stuff.

data = utf8_data.decode('utf-8')
for row in csv.reader(data, dialect=csv.excel, ...):
    # ...

Answer 2

Python 3 has excellent unicode support already. Any time you open a file in text mode, you can use a specific encoding, or let it default over to UTF-8. There is no longer a difference between str and unicode in Python 3. The latter does not exist, and the former has full unicode support. This simplifies your job greatly since you don't need your setup method at all. You can just iterate over a normal csv.reader .

As an additional note, you should always open files in a with block, so things get cleaned up if there is any kind of exception. As a bonus, your file will get closed automatically when the block ends:

with open(filename) as f:  # The default mode is 'rt', with utf-8 encoding
    for question, answer in csv.reader(f):
        # Do your thing here. Both question and answer are normal strings

This will only work properly if you are sure that each row contains exactly 2 elements. You may be better off doing something more like

with open(filename) as f:  # The default mode is 'rt', with utf-8 encoding
    for row in csv.reader(f):
        if len(row) != 2:
            continue  # Or handle the anomaly by other means
        question, answer = row
        # Do your thing here as before