I have my array unique that is my main array and my array kind. I need to check that only 1 value of kind is present in the array unique. Then if there is more than 1 value of the array kind in unique I need to unset all values but the first one used in the array.
The further i got to achieve this is with the following code but I can not store the indexpath of the found object to do a later comparison. xcode says "bad receiver type nsinteger"
could anyone help me to achieve this?
kind = #[#"#Routine",#"#Exercise",#"#Username"];
NSMutableArray *uniqueKind = [NSMutableArray array];
for (NSString* obj in kind) {
if ( [unique containsObject:obj] ) {
NSInteger i = [unique indexOfObject:obj];
[uniqueKind addObject: [i intValue]];
}
}
An NSInteger is like an int, so you can't send it a message ([i intValue]). Also, you can't add an NSInteger to an array without making it an NSNumber or some other object type. You can do it like this:
NSInteger i = [unique indexOfObject:obj];
[uniqueKind addObject: [NSNumber numberWithInteger:i]];
Also (without understanding what you're doing) you might want to use an NSSet instead of an array. And you can combine a couple of calls:
NSUInteger i = [unique indexOfObject:obj];
if ( i != NSNotFound ) {
[uniqueKind addObject:[NSNumber numberWithInteger:i]];
}
I'm not sure if it would solve your problem, but have you considered using sets (or mutable variation) instead of arrays? They ensure uniqueness and they allow you to check for intersection/containment. See the NSSet class reference.
You have to add objects to the NSMutableArray, not the actual intValue. Try converting teh integer to a NSNumber first.
[uniqueKind addObject: [NSNumber numberWithInt:i]];
instead.
(edited )
Related
I am an Obj-C newbie so this might be an obvious question.
I am adding 10 numbers as keys to an NSMutableDictionary with value 0 for all of them. Something like this --
for( i=1; i<10; i++)
{
[dict setObject:[NSNumber numberWithInt:0] forKey:[NSNumber numberWithInt:i]];
}
Now at a later point in code I want to get the object stored for the key number and obtain its value. In this case for e.g. for number 3 as key we stored the value 0. For this I use this code -
id numberObj = [game objectForKey:[NSNumber numberWithInt:3]];
int numberObjValue = ????
I see id in the debugger as pointing to 0. But I am not sure how to get it into an integer variable I declared. Hope that makes sense.
I print numberObj and some address is printed as expected. How do I turn this generic id into a NSNumber and subsequently store it in numberObjValue?
id is not a datatype. It simple means it can return any object type. When you are sure you have inserted an NSNumber, you simply get it's value into an NSNumber.
NSNumber* myNumber = [myDict objectForKey:key];
That's it. If you want to make sure it is actually an NSNumber being returned, use isKindOfClass:.
The object is already an NSNumber. You put an NSNumber in, and you got an NSNumber out. There is no conversion necessary. You can assign it to an NSNumber variable, but the object would not be any more or less an NSNumber for having done so. So you don't need to turn it into an NSNumber, and you can get the number's integer value in the usual way you do with all NSNumbers.
You can get the number from the dictionary and then store it in an int using intValue:
NSNumber *numberObj = (NSNumber *)[game objectForKey:[NSNumber numberWithInt:3]];
int numberObjValue = [numberObj intValue];
Or, you can do it with one line:
int numberObjValue = [[game objectForKey:[NSNumber numberWithInt:3]] intValue];
I have 3 objects that might be or not initialized in a random order.
so, if objects "objectOne, "objectTwo", "objectThree" are initialized in this order with
myArray = [NSArray arrayWithObjects:objectOne,objectTwo,objectThree nil];
all objects get inside the array without problem but in my case objectOne, objectTwo might be nil and objectThree might not be nil, and in this case I would like myArray to return(count) 1.
if objectOne is nil but objectTwo and objectThree are not nil I want my array to return(count) 2.
In these 2 last cases my array always return nil. What would be the best approach to this?
There are no magic method can solve the problem for you, you need to build the array from NSMutableArray
NSMutableArray *array = [NSMutableArray array];
if (objectOne) [array addObject:objectOne];
if (objectTwo) [array addObject:objectTwo];
if (objectThree) [array addObject:objectThree];
arrays can't contain nil. There is a special object, NSNull ([NSNull null]), that serves as a placeholder for nil. You can put NSNull in an array, but I don't think that solves your problem either.
How about this:
Create an empty mutable array.
In 3 separate statements:
If objectOne is not nil, add it to the array
if objectTwo is not nil, add it to the array
If objectThree is not nil, add it to the array.
If you need your objects to be in random order, scramble the array afterwords:
for (int index = 0; index < array.count; index++)
{
int randomIndex = arc4random_uniform()
[array exchangeObjectAtIndex: index withObjectAtIndex: randomIndex];
}
This is known as a Fisher–Yates shuffle. (or a minor variation on Fisher-Yates, anyway.)
If you're doing this rarely and you aren't trying to make things neat, you can, of course, use a mutable array and either add or don't add the items one at a time in code, depending on whether they are nil.
If you're doing this frequently and you want a syntax that looks similar to the array literal notation, you can take advantage of the C preprocessor and C arrays to create a smarter NSArray class constructor that handles nil:
#define NSArrayWithCArray(array) \
[NSArray arrayWithCArray:cArray count:sizeof(cArray) / sizeof(cArray[0])];
id cArray[] = {
object1,
object2,
object3,
...
};
NSArray *array = NSArrayWithCArray(cArray);
and then define a method on NSObject that walks through the C array programmatically, dropping any nil values.
+ (NSArray *)arrayWithCArray:(__strong id[])cArray count:(NSUInteger)count {
NSMutableArray *array = [NSMutableArray arrayWithCapacity:count];
for (__strong id *item = cArray; item < cArray + count; item++) {
if (*item != nil) {
[array addObject:*item];
}
}
return array;
}
Note: The code above is untested, but at least close enough to give you an idea of how to do it. :-)
I have array of objects and some objects in it have the same value(for example user's guid).
I want find all object with same guide and remove all of then rather then first.
What is the best way to do it?
You can use the NSMUtableArray's removeObject method. Notice that your object should implement the isEqual method appropriately.
[NSMutableArray removeObject]
as per the description:
This method uses indexOfObject: to locate matches and then removes
them by using removeObjectAtIndex:. Thus, matches are determined on
the basis of an object’s response to the isEqual: message. If the
array does not contain anObject, the method has no effect (although it
does incur the overhead of searching the contents).
So, first of all you array need to be mutable NSMutableArray, then the process is:
consider the actual object;
check if is present another object equal to this in the other objects;
if yes, delete the equal objects include the actual.
-
NSMutableArray *arr = [NSMutableArray arrayWithArray:#[#1, #2, #3, #2, #5, #3]];
for(int i=0; i<[arr count]; i++) {
id obj = arr[i];
if([arr indexOfObject:obj inRange:NSMakeRange(i+1, [arr count]-i-1)] != NSNotFound) {
[arr removeObject:obj inRange:NSMakeRange(i, [arr count]-i)];
i--;
}
}
This question already has answers here:
How do I sort an NSMutableArray with custom objects in it?
(27 answers)
Closed 9 years ago.
Hopefully someone can help.
I'm adding multiple objects to a NSMutableArray and I need to sort the order based on the first element which will always be a number.
However I'm unsure how to do this?
For example:
NSMutableArray *array = [[NSMutableArray alloc] init];
NSArray *object = [NSArray arrayWithObjects: #"1",#"Test",#"Test"];
[array addObject:object];
Thanks
If your array always contains other arrays, and the first element of the innermost array is always a string containing a number, you could use the NSMutableArray method sortUsingComparator to sort your array:
[array sortUsingComparator: ^(NSArray* obj1, NSArray* obj2)
{
int value1 = [obj1[0] integerValue];
int value2 = [obj2[0] integerValue];
if (value1==value2)
return NSOrderedSame;
else if (value1 < value2)
return NSOrderedAscending;
else
return NSOrderedDescending;
}
];
In the sortUsingComparator family of methods, you supply a block of code that the sort method uses to compare pairs of objects in your array. The block uses the standard typedef NSComparator, which takes 2 objects as parameters and returns a value of type NSComparisonResult.
The code above will probably crash if all the objects in your array are not arrays of strings. (Actually it would work if the first element of each component array was an NSNumber, since NSNumber also responds to the integerValue message.)
If you are going to use this code in a very controlled environment where you can be sure that the data you are sorting is well-formed, it should work as written. If there is any chance that the objects in the array would be of a different type, or be empty, or that their first element would not respond to the integerValue messages, then you should add error checking code.
If you sort your array alphanumerically, the object #"1" will appear before any words. Keep in mind though that #"1" in your code above is a string, not a number.
As to how to sort an array, look into [NSArray sortedArrayUsingComparator:] and similar methods.
I have a problem which I can't solve for a long time. I have a JSON response from the server which is parsed to NSDictionary lastMsgs as in the image below:
So for example 1323 it's a key and it associated with NSDictionary (which contains keys such as body, subject etc and values). So the problem I need in some way delete an entry which nested NSDictionary value has entry : type = 1. I don't know how to do this. I tried to do this:
NSMutableArray* _ModelVals = [[lastMsgs allValues] mutableCopy];
for (int i =0; i<[_ModelVals count]; i++) {
string_compare = [NSString stringWithFormat:#"%#" , [_ModelVals objectAtIndex:i]];
if ([string_compare rangeOfString:#"type = 1"].location != NSNotFound) {
[_ModelVals removeObjectAtIndex:i];
}
}
But it is work not correctly and delete not all entries which has type = 1. So the question - how can I implement this and delete entry in nested NSDictionary?
There is no value "type = 1" in the dictionary. That's just the log. You get the value of a key in a dictionary using [dict objectForKey:#"key"] or dict[#"key"].
Judging from your log, the type seems to be an NSNumber, not an NSString. Just get the int representation of it (assuming the type is an integer) and use a simple C int to int comparison.
And you can't filter an array like that. You will skip an entry. If you remove an entry, you have to decrease i by 1.
Or use this simpler solution:
NSSet *keys = [lastMsgs keysOfEntriesPassingTest:^BOOL(id key, id obj, BOOL *stop) {
return [obj[#"type"] intValue] == 1;
}];
NSMutableDictionary *dict = [lastMsgs mutableCopy];
[dict removeObjectsForKeys:[keys allObjects]];
This will first collect the keys of all objects (dictionaries) that have a type of 1 and then remove those from a mutable copy of the original dictionary.
You cannot add or remove objects from a collection while enumerating though it. I would create a another array that you can store references to the objects that you want to delete and remove them after you have looped though it.