iphone - exception 'NSInvalidArgumentException':-[__NSArrayM objectForKey:]: unrecognized selector sent to instance 0x752c670 -

this question has answer here:

• sbjson execptions after parsing (__nsarraym objectforkey:) 1 answer

i use sbjson parse json, json i'm trying parse :

{"r":"0","s":"","t":"","m":[{"c00":"2013-08-16 17:35:03"}]} 

and code:

nsstring *response = [self post:@"9903" content:payload state:@""]; nsdictionary *dict = [response jsonvalue]; nsstring *result = [dict objectforkey:@"r"]; nslog(@"result=%@",result); if ([@"0" isequaltostring:result]) {     nsdictionary *msg = [dict objectforkey:@"m"];     nsstring *c00 = [msg objectforkey:@"c00"];//here exception statement     nsstring *tokenstring = [nsstring stringwithformat:@"%@",c00];     nslog(@"tokenstring%@",tokenstring);     return tokenstring; }else {     return nil; } 

the exception log:

2013-08-16 17:45:44.902 vep[4731:c07] -[__nsarraym objectforkey:]: unrecognized selector    sent instance 0x7250300 2013-08-16 17:45:44.903 vep[4731:c07] *** terminating app due uncaught exception 'nsinvalidargumentexception', reason: '-[__nsarraym objectforkey:]: unrecognized selector sent instance 0x7250300' 

what's wrong? help!

because key 'm:' contain array of dictionary not dictionary. so, write a,

nsdictionary *msg = [[dict objectforkey:@"m"] objectatindex:0];