What is the right code pattern for NSNumberFormatter?

Question

What is the right code pattern for NSNumberFormatter?

There are many example on the Internet (including this one: http://mac-objective-c.blogspot.com/2009/04/nsnumberformatter-some-examples.html) where the NSNumberFormatter is allocated and initialized each time it is needed.

Yet some other examples in the Apple Documentation (including International Mountains) prefer to use it as a private property. Another example (Locations) use it through a static variable.

How do you use an NSNumberFormatter? What is the most efficient technique?

Answer 1

NSNumberFormatter is not an excessively complicated object, so unless you're using it frequently in a tight loop, efficiency doesn't really matter.

With that said, I'd tend to default to keeping it around in a static variable, if you're trying to minimize the number of instances you create.

Answer 2

I think the examples are just showing how to create and use the formatters, not necessarily the most efficient way to use them. My rule of thumb is if the code will use them more than once, I keep them around somewhere. This also makes debugging and maintenance easier.

Answer 3

Here is one more example set that may be of help for those new to NSNumberFormatter:

Formatting Numbers – NSNumberFormatter Examples