stringWithFormat with varying number of arguments

[harrytheshark]

I'm wondering the best way to approach the following problem,

My app downloads from a website a string with looks something like this:

"I have 3 parameters. The first is %@, the second is %@ and the third is %@"

I know I can using stringWithFormat like this to pass three parameters:

NSString * downloadedString = @"I have 3 parameters. The first is %@, the second is %@ and the third is %@";
NSString * formattedString = [NSString stringWithFormat:downloadedString,firstValue,secondValue,thirdValue];

What I'm not sure how to do is pass a varying number of parameters/arguments to stringWithFormat.

Let's say for instance that the string that's being downloaded changed to:

"4 params. 1 = %@, 2 = %@, 3 = %@ and 4 = %@"

Instead of rewriting the code, it would be good if the app could just deal with it, working out there is 4 arguments this time, and passing 4 to it.

I can tell the app how many arguments there are going to be, I can also tell the app what those arguments should be, what I'm uncertain on is how code for the changes.

Something like:

NSArray * arrayContainingArguments = [[NSArray alloc] initWithObjects:@"first",@"second",@"third",@"forth",nil];
NSString * downloadedString = @"4 params. 1 = %@, 2 = %@, 3 = %@ and 4 = %@";
NSString * finalString = [NSString stringWithFormat:downloadedString,arrayContainingArguments];
[arrayContainingArguments release];

Any ideas?

Tom.

[smasher]

I think you'll have to write your own method for this that takes an array and returns a string.

Your method could create a new NSMutableString, loop through the array calling appendString or appendFormat, and then returning the final string.

[harrytheshark]

Thanks for the reply and idea.
I managed to stumble across initWithFormat:arguments in the documentation and have got something working from that.

Thanks again,
Tom.

[kenji]

Hi could you post some code how you did it?
I'm trying to do this kind of string formatting too.

[kenji]

Nevermind, found another post with a sample. Anyways, thanks for the hint

How to "pass on" a variable number of arguments to NSString's +stringWithFormat: - Stack Overflow