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I'm calling some JSON and parsing relevant data as CSV. I cannot figure out how to fill in the intermediate JSON dict file with default keys, as many are unpopulated. The result is a KeyError as I attempt to parse the content into a CSV.
I'm now receiving a 'NoneType' error for (manufacturer):
import urllib2, json, csv, sys, os, codecs, re from collections import defaultdict output = 'bb.csv' csv_writer = csv.writer(open(output, 'w')) header = ['sku', 'name', 'description', 'image', 'manufacturer', 'upc', 'department', 'class', 'subclass'] csv_writer.writerow(header) i=1 while i<101: print i bb_url = urllib2.Request("http://api.remix.bestbuy.com/v1/products(sku=*)?show=sku,name,description,image,manufacturer,upc,department,class,subclass&format=json&sort=sku.asc&page=" + str(i) + "&pageSize=100&apiKey=*****************") bb_json = json.load(urllib2.urlopen(bb_url)) print bb_json for product in bb_json['products']: row = [] row.append(product['sku']) if product['name']: row.append(str((product['name']).encode('utf-8'))) else: row.append("") row.append(str(product.get('description',""))) row.append(str(product['image'])+ " ") if product['name']: row.append(str(product.get('manufacturer',"").encode('utf-8'))) else: row.append("") row.append(str(product.get('upc','').encode('utf-8'))) row.append(str((product['department']).encode('utf-8'))) row.append(str((product['class']).encode('utf-8'))) row.append(str((product['subclass']).encode('utf-8'))) csv_writer.writerow(row) i = i+1 
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Avoiding KeyError when accessing Dictionary Key We can avoid KeyError by using get() function to access the key value. If the key is missing, None is returned. We can also specify a default value to return when the key is missing.
The Usual Solution: . If the KeyError is raised from a failed dictionary key lookup in your own code, you can use . get() to return either the value found at the specified key or a default value.
The defaultdict is a subdivision of the dict class. Its importance lies in the fact that it allows each new key to be given a default value based on the type of dictionary being created. A defaultdict can be created by giving its declaration an argument that can have three values; list, set or int.
A defaultdict works exactly like a normal dict, but it is initialized with a function (“default factory”) that takes no arguments and provides the default value for a nonexistent key. A defaultdict will never raise a KeyError. Any key that does not exist gets the value returned by the default factory.
You can use your_dict.get(key, "default value") instead of directly referencing a key.
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