nsnumber

I'm having problems with converting NSNumber to string and string to NSNumber . Here's a sample problem: NSString *stringValue = @"9.2"; NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init]; NSLog(@"stringvalue:%@",[[formatter numberFromString: stringValue] stringValue]); Output will be: stringvalue:9.199999999999999 I need to retrieve the original value, where, in the example should be 9.2 . On the contrary, when the original string is 9.4 the output is still 9.4 . Do you have any idea how to retrieve the original string value without NSNumber doing anything about it? You are

How do I check if a NSNumber object is nil or empty? OK nil is easy: NSNumber *myNumber; if (myNumber == nil) doSomething But if the object has been created, but there is no value in it because an assignment failed, how can I check this? Use something like this? if ([myNumber intValue]==0) doSomething Is there a general method for testing objects on emptiness like for NSString available (see this post )? Example 1 NSMutableDictionary *dict = [[NSMutableDictionary alloc] init]; [dict setValue:@"" forKey:@"emptyValue"]; NSNumber *emptyNumber = [dict objectForKey:@"emptyValue"]; Which value does

I am having an issue with an NSNumber variable "num" that is currently containing 0.522000003606 I looked up several other issues on stackoverflow with others having the same issue but nothing. My project is currently using ARC so I think some features are unavailable, that is, unless I disallow ARC within the class I am currently wanting to set the precision of the NSNumber. I understand NSNumberFormatter is the basic setPrecision class function I must use but I am having issues.... Everytime i use NSNumberFormatter, it spits back NULL!!! nowValue = [now objectForKey:@"value"]; // This is

It seems to me that any valid number can also be expressed as a String , so I don't know why this function returns a String? instead of a String . My best guess would be because of the legacy support. This is from the official documentation: The behavior of an NSNumberFormatter object can conform either to the range of behaviors existing prior to OS X v10.4 or to the range of behavior since that release. NSNumberFormatter Class Reference 来源： https://stackoverflow.com/questions/28103113/does-nsnumberformatter-stringfromnumber-ever-return-nil

I an developing some code in which I use a scanner to get to NSNumbers from a string, say x and y. Now I want to compute something simple from x and y, say, z = 10.0/(x + y/60.0)/60.0). I can't do this directly, since the compiler doesn't like ordinary arithmetic symbology applied to number objects. So, I tried defining xD and yD, of type double, and then tried a type conversion xD = (double) x; yD = (double) y; but that also gives a compile error. Just how does one get NSNumber objects converted to be used in ordinary arithmetic expressions? I did considerable browsing of the literature, and

Is it possible to see the numeric value of an NSNumber in the debugger datatip on in the variable watch window? I store an Integer value in NSNumber and want to see this value during debugging. I tried some of the data formatters in the debugger already, but it wasn't much help. Open the Debugger view and in the Summary column enter {(int)[$VAR intValue]} or whatever interpretation is most appropriate for what you want to see in the Debugger. 来源： https://stackoverflow.com/questions/753153/xcode-debugging-view-value-of-nsnumber