Updating key in NSMutableDictionary - objective-c

Question

json is a NSMutableDictionary with a key "message". I need to "clean" the data in that key using stringByReplacingOccurrencesOfString
NSLog(#"json: %#", json); outputs this:
json: {
conversationId = 61;
countmessagesinconversation = 2;
message = "Messages exist!";
messagesinconversation = (
{
message = "Hi";
messagecreated = "June 24, 2013 16:16";
messageid = 68;
sentby = Thomas;
sentbyID = 1;
title = "Subject";
},
{
message = "What's up?";
messagecreated = "September 22, 2013 17:00";
messageid = 331;
sentby = Steve;
sentbyID = 2;
title = "Subject";
}
);
success = 1;
}
So, this is what I've come up with, but I'm clearly getting it all wrong.
NSString *newstr = [[NSString alloc]init];
for (newstr in [[[json objectForKey:#"messagesinconversation"]allKeys]copy]){
newstr = [newstr stringByReplacingOccurrencesOfString:#" "
withString:#""];
[json setValue:newstr forKey:#"message"];
}
Could somebody please help me out with this and explain so I understand the concept? I know how to do this with an array but what my problem is (I think) is that I do not fully understand how to access the right key in the dictionary.
Edit: Sorry for not being clear in my question. What happens is that if there are two space characters in the key message then " " shows up when I display it on the screen.

Answer 1

//First get the array of message dictionaries:
NSArray * messages = [json objectForKey:#"messagesinconversation"];
//create new array for new messages
NSMutableArray * newMessages = [NSMutableArray arrayWithCapacity:messages.count];
//then iterate over all messages (they seem to be dictionaries)
for (NSDictionary * dict in messages)
{
//create new mutable dictionary
NSMutableDictionary * replacementDict = [NSMutableDictionary dictionaryWithDictionary:dict];
//get the original text
NSString * msg = [dict objectForKey:#"message"];
//replace it as you see fit
[replacementDict setObject:[msg stringByReplacingOccurrencesOfString:#" " withString:#""] forKey:#"message"];
//store the new dict in new array
[newMessages addObject:replacementDict];
}
//you are done - replace the messages in the original json dict
[json setObject:newMessages forKey:#"messagesinconversation"];

Answer 2

Add your array of dictionary in another mutable array
NSMutableArray *msgArray = [[json objectForKey:#"messagesinconversation"] mutableCopy];
Use for loop for access it.
for (int i = 0 ; i < msgArray.count ; i++)
{
[[[msgArray objectAtindex:i] objectForKey:#"message"] stringByReplacingOccurrencesOfString:#" " withString:#""];
}
[self.mainJSONDic setValue:msgArray forKey:#"messagesinconversation"];
Try this code might helpful in your case:

Answer 3

Now that the requirements are more clear I'll try an answer. I try to use the same names as in your question and suggested in erlier answers.
Make json an NSMUtableDictionary where you declare it. Then go forward:
json = [json mutableCopy]; // creates a mutable dictionary based on json which is immutable as result of the json serialization although declared as mutable.
NSMutableArray *msgArray = [[json objectForKey:#"messagesinconversation"] mutableCopy]; //this fetches the array from the dictinary and creates a mutable copy of it.
[json setValue:newstr forKey:#"messagesinconversation"]; // replace the original immutable with the mutable copy.
for (int i = 0; i < [msgArray count]; i++) {
NSMutableDictionary mutableInnerDict = [[msgArray objectAtIndex:i] mutableCopy]; // fetching the i-th element and replace it by a mutable copy of the dictionary within.
[msgArray replaceObjectAtIndex:i withObject:mutableInnerDict]; // it is now mutable and replaced within the array.
NSString *newString = [[[msgArray objectAtindex:i] objectForKey:#"message"] stringByReplacingOccurrencesOfString:#" " withString:#" "]; // crates a new string with all &nbsp removed with blanks.
[mutableInnerDict setValue:newString forKey:#"message"];
}
Regarding the replacement of &nbsp with " ", is this really what you want? I am asking because &nbsp does not occur in your sample data. Or do you want to remove blanks at all?