how to set NSDictionary without Keys - iphone

Question

i have two arrays stored in dictionary:
array1=[[NSArray alloc]initWithObjects:a,b,c,d,e, nil];
array2=[[NSArray alloc]initWithObjects:1,2,3, nil];
NSDictionary * dic=[[NSDictionary alloc]initWithObjects:array1 forKeys:array2];
if i run i am getting error as:
-[NSDictionary initWithObjects:forKeys:]: count of objects (0) differs from count of keys (1)'
now i want to set dictionary only for a,b,c with keys: 1,2,3.
were as the arrays can't be edited
how can i do that

Answer 1

It does not make sense to add keys for nil values.
NSRange range = NSMakeRange(0, MIN(array1.count, array2.count));
NSDictionary * dic=[[NSDictionary alloc]initWithObjects:[array1 subarrayWithRange:range]
forKeys:[array2 subarrayWithRange:range]];

Answer 2

Use as :
array1=[[NSArray alloc]initWithObjects:a,b,c,d,e, nil];
array2=[[NSArray alloc]initWithObjects:1,2,3, nil];
// NSDictionary * dic=[[NSDictionary alloc]initWithObjects:array1 forKeys:array2];
NSMutableDictionary * dic=[NSMutableDictionary new];
for(int i=0 ; i< array2.count ; i++ ){
[dic setObject:array1[i] forKey:array2[i]];
}

Answer 3

Use NSMutableArray to work with the first array
remove d & e from it

Answer 4

From the Doc:
Neither a key nor a value can be nil; if you need to represent a null value in a dictionary, you should use NSNull.

Answer 5

A single key for the whole array is simple to set:
NSDictionary * dic=[[NSDictionary alloc]initWithObjects:array1 forKeys:#"Array"];
And if you want to add a key to each of the object in array, it goes like this:
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
int key = 1;
for (NSString *str in array1) {
[dict setObject:str forKey:[NSString stringWithFormat:#"%d",key]];
key++;
}
Hope this helps!!!