Convert NSNumber to NSDecimalNumber

Question

I realize that NSDecimalNumber inherits from NSNumber.

However, I am struggling to figure out how I can init an NSDecimalNumber from an NSNumber or how to convert an NSNumber to an NSDecimalNumber.

I have tried

NSDecimalNumber* d = [aNumber copy];

where aNumber is an NSNumber object to no avail.

Am I missing something?

Thanks.

Solution 1

You can do:

NSDecimalNumber *decNum = [NSDecimalNumber decimalNumberWithDecimal:[aNumber decimalValue]];

Solution 2

So:

NSNumber * number = [NSNumber numberWithInt:10];
NSDecimalNumber *d = [NSDecimalNumber decimalNumberWithDecimal:[number decimalValue]];

And in Swift

let number = NSNumber(int: 10)
let dec = NSDecimalNumber(decimal: number.decimalValue)

Comments

[rmaddy]

The 2nd one isn't valid (and in both cases d needs to be a pointer).

[Michael Rivers]

Only problem is that passing an NSNumber with value of 2e+34 ends up with decNum of 2 and 34 zeros. would like it to maintain the same mantissa and exponent.

[rmaddy]

2e+34 is 2 with 34 zeros. Those are the same number expressed in two different ways.

[pronebird]

@rmaddy what are you talking about?

[rmaddy]

@Andy The answer has been edited twice (as of this comment) since my original comment. Look at the edit history to see what the answer looked like at the time of my comment.