Python dictreader - jak zmienić małe kolumny w CSV?

Question

Mam plik CSV z nazwami kolumn dużymi literami. Czytam dane przy użyciu csv.dictreader, ale potrzebuję nazw kolumn małymi literami.

znalazłem ten kod tutaj Accessing csv header white space and case insensitive

import csv 

class DictReaderInsensitive(csv.DictReader): 
    # This class overrides the csv.fieldnames property. 
    # All fieldnames are without white space and in lower case 

    @property 
    def fieldnames(self): 
     return [field.strip().lower() for field in super(DictReaderInsensitive, self).fieldnames] 

    def __next__(self): 
     # get the result from the original __next__, but store it in DictInsensitive 

     dInsensitive = DictInsensitive() 
     dOriginal = super(DictReaderInsensitive, self).__next__() 

     # store all pairs from the old dict in the new, custom one 
     for key, value in dOriginal.items(): 
      dInsensitive[key] = value 

     return dInsensitive 

class DictInsensitive(dict): 
    # This class overrides the __getitem__ method to automatically strip() and lower() the input key 

    def __getitem__(self, key): 
     return dict.__getitem__(self, key.strip().lower()) 

Moim problemem jest to, że gdy uruchamiam to z

datafile = open(self.ifs_data_file,'rU') 
     csvDict = DictReaderInsensitive(datafile) 
     for row in csvDict: 
      print row 
      #self.db.ifs_data.insert(**row) 
      #self.db.commit() 

otrzymuję ten błąd

Traceback (most recent call last): 
    File "D:\Development\python\supplier_review\supplier_review.py", line 239, in update_ifs_data 
    for row in csvDict: 
    File "D:\Python27_5\lib\csv.py", line 103, in next 
    self.fieldnames 
    File "D:\Development\python\supplier_review\supplier_review.py", line 288, in fieldnames 
    return [field.strip().lower() for field in super(DictReaderInsensitive, self).fieldnames] 
TypeError: must be type, not classobj 

Answer 1

DictReader jest starym stylu obiekt, więc super() tutaj nie działa. Musisz uzyskać bezpośredni dostęp do obiektu property w klasie nadrzędnej. W Pythonie 2, chcesz zastąpić metodę .next(), nie .__next__():

class DictReaderInsensitive(csv.DictReader): 
    # This class overrides the csv.fieldnames property. 
    # All fieldnames are without white space and in lower case 

    @property 
    def fieldnames(self): 
     return [field.strip().lower() for field in csv.DictReader.fieldnames.fget(self)] 

    def next(self): 
     return DictInsensitive(csv.DictReader.next(self)) 

Demo:

>>> example = '''\ 
... foo,Bar,BAZ 
... 42,3.14159,Hello world!'''.splitlines() 
>>> csvDict = DictReaderInsensitive(example) 
>>> row = next(csvDict) 
>>> print row 
{'bar': '3.14159', 'foo': '42', 'baz': 'Hello world!'} 
>>> row['BAZ'] 
'Hello world!' 

Answer 2

Można małe litery pierwszy wiersz pliku przed przekazaniem go do DictReader:

import csv 
import itertools 

def lower_first(iterator): 
    return itertools.chain([next(iterator).lower()], iterator) 

with open(ifs_data_file, 'rU') as datafile: 
    csvDict = csv.DictReader(lower_first(datafile)) 
    for row in csvDict: 
     print row  

Answer 3

Aby uzyskać znacznie prostsze podejście, wystarczy zaktualizować atrybut DictReader.fieldnames przed uzyskaniem dostępu do słownika, jak w:

>>> f = open('example-x-y-time.csv', 'rb') 
>>> reader = csv.DictReader(f) 
>>> reader.fieldnames 
['Latitude', 'Longitude', 'Date'] 
>>> print next(reader) 
{'Latitude': '44.8982391', 'Date': '2004-07-12', 'Longitude': '-117.7791061'} 
>>> reader.fieldnames = [name.lower() for name in reader.fieldnames] 
>>> print next(reader) 
{'latitude': '44.6637001', 'date': '1964-04-03', 'longitude': '-123.5997009'}