[kman42]

I am trying to make an NSNumber from a string. I noticed that there is an NSDecimarNumberWithString method, but nothing analogous for NSNumber. Is there an easy way to do it?

thanks,
kman

[resImadA]

You can do a:

[NSNumber numberWithInt:[theString intValue]];


Not sure if it's the most efficient means though

[CharlesS]

Read the docs for NSScanner. It does what you want.

[kman42]

On a larger note. I guess I don't really understand when I would want to use an int v. an NSNumber. I don't seem to be able to do arithmetic with NSNumbers. Maybe I'm just going about it wrong.

kman

[resImadA]

NSNumbers are really only useful when you're building an NSArray, putting keys in a dictionary (like a preference file), or other very cocoa-y things.

In those cases, Apple's functions have been set up to deal only with classes. Any function that wants a type of (id) can only be passed a class.

So the problem comes in where you need to get an integer in there. NSNumber is really just a "wrapper" around a regular int/float/double variable. So you "hide" your int inside an NSNumber and pass it to the function. The same kind of deal happens with NSStrings, which can be thought of as a simple wrapper around a standard c string.

Most of the time you'll be using regular old C/C++ style ints.


Let me know if I've completely confused you

[kman42]

Nevermind. I just figured out that I have to message the NSNumber with intValue.

edit: I was obviously posting this just as reslmadA was giving his wonderful description.


kman

[ 04-02-2002: Message edited by: kman42 ]