i'm in a bit of a situation here...
i am passing a string to a function and in that function i need to create an array whose name is the value of the string.
Say, for example: -(void) function : (NSString *) arrayName; //let arrayName = @"foo";
In this function I need to create an array named "foo" i.e the value of the passed parameter.
Can anyone help please :|
Thanks in advance ;)
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Why do you need to have an NSArray variable have a particular name?Joubert Nel– Joubert Nel2010-09-15 05:52:03 +00:00Commented Sep 15, 2010 at 5:52
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3 Answers
Arrays don't have names. Variables have names, but variables are local to their scope, so once you leave the scope of that method, having a variable named "foo" is pointless; you can name the variable whatever you want and it will work just fine. Ex:
- (void) function:(id)whatever {
NSArray * myVariable = [NSArray arrayWithStuff....];
//use myVariable
}
What are you really trying to do?
2 Comments
bangdel
hey thanks for your opinion... :) Actually the function is recursive in nature; so everytime i iterate through it, i want to be able to create a new array without losing the previous one...
Dave DeLong
@Bangdel if the method is recursive, then the object will still exist in the frame/scope in which it was created. Once you exit the recursive call, the object will still be there.
That is not possible in Objective-C, but you can use e.g. a dictionary that maps a string to an array.
E.g. assuming something like the following property:
@property (readonly, retain) NSMutableDictionary *arrays;
... you can store an array by name:
- (void)function:(NSString *)arrayName {
NSArray *array = [NSArray arrayWithObjects:@"foo", @"bar", nil];
[self.arrays setObject:array forKey:arrayName];
}
... and access it like so:
NSArray *array = [self.arrays objectForKey:arrayName];
Comments
C is a compiled language where any source code names (for variables, functions, etc.) are not available at runtime (except for perhaps optionally debugging, -g). The Objective C runtime adds to this the ability to look up Obj C methods and classes by name, but not objects, nor any C stuff. So you're out of luck unless you build your own mini-language-interpreter structure for reference-by-name. Lots of ways to do this, but simple languages usually build some sort of variable table, something like a dictionary, array, or linked-list of objects (structs, tuples, etc.) containing string name, object pointer (maybe also type, size, etc.).
