Accessing csv header white space and case insensitive

Question

I\'m overriding the csv.Dictreader.fieldnames property like the following to read all headers from csv files without white space and in lower case.

Answer 1

Based on Pedro Romano's suggestion I coded the following example.

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())

For a file containing headers like

• "column_A"
• " column_A"
• "Column_A"
• " Column_A"
• ...

you can access the columns like this:

csvDict = DictReaderInsensitive(open('csv-file.csv', 'rU'))

for lineDict in csvDict:
    print(lineDict[' Column_A']) # or
    print(lineDict['Column_A']) # or
    print(lineDict[' column_a']) # all returns the same

Answer 2

You'll have to do it in two steps:

1. Create your dict specialisation with a __getitem__ method that applies the .strip().lower() to the its key parameter.
2. Override __next__ on your MyDictReader specialised class to return one of your special dictionaries initialised with the dictionary returned by the csv.DictReader superclass's __next__ method.