Question

I have the following JSON array:

[u'[e-mail]']

“u” is apparently the unicode character, and it was automatically created by Python. Now, I want to bring this back into Objective-C and decode it into an array using this:

+(NSMutableArray*)arrayFromJSON:(NSString*)json
{
    if(!json) return nil;
    NSData *jsonData = [json dataUsingEncoding:NSUTF8StringEncoding];
   //I've also tried NSUnicodeStringEncoding here, same thing
    NSError *e;
    NSMutableArray *result= [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&e];
    if (e != nil) {
        NSLog(@"Error:%@", e.description);
        return nil;
    }
    return result;
}

However, I get an error: (Cocoa error 3840.)" (Invalid value around character 1.)

How do I remedy this?

Edit: Here’s how I bring the entity from Python back into objective-c:

First I convert the entity to a dictionary:

def to_dict(self):
    return dict((p, unicode(getattr(self, p))) for p in self.properties()
                if getattr(self, p) is not None)

I add this dictionary to a list, set the value of my responseDict[‘entityList’] to this list, then self.response.out.write(json.dumps(responseDict))

However the result I get back still has that ‘u’ character.

Answer 1

[u’[e-mail]’] is the decoded python value of the array it is not valid JSON.

The valid JSON string data would be just ["[e-mail]"].

Dump the data from python back into a JSON string by doing:

import json
python_data = [u'[e-mail]']
json_string = json.dumps(data)

The u prefix on python string literals indicates that those strings are unicode rather than the default encoding in python2.X (ASCII).