json - ios: Compare NSString to "<null>" not working -

i consuming web service returns json. 1 of values "< null >".

when run follwoing code if statment still executed when not suppposed to.

any reason why?

nsdictionary *location = [dictionary valueforkey:@"geolocation"];       //get product name nsstring *latitude = [location valueforkey:@"latitude"]; nslog(@"%@", latitude);  nsstring *longitude = [location valueforkey:@"longitude"];  if (![latitude isequal: @"<null>"] && ![longitude isequal: @"<null>"]) {     nslog(@"%d", i);     cllocationcoordinate2d coordinate;     coordinate.longitude = [latitude doublevalue];     coordinate.longitude = [longitude doublevalue];     [self buildmarketslist:coordinate title:title subtitle:nil]; //build browse list product } 

i consuming web service returns json. 1 of values "< null >"

aha. 2 possibilities:

i. json doesn't contain latitude , longitude information. in case, keys them aren't present in dictionary you're getting back, in fact obtaining nil (or null) pointer. messaging nil returns zero, both conditions fire (due negation applied). try instead:

if (latitude != nil && longitude != nil) 

and never rely on description of object.

ii. json contains null values, , json parser you're using turns null [nsnull null], , in turn you're trying compare string against nsnull. in case, try this:

if (![latitude isequal:[nsnull null]] && ![longitude isequal:[nsnull null]])