Comparing object indexes of two Arrays - ios

Question

My problem is...
I have data that gets pulled from a XML file and parsed then stored in an array.
This data is updated every ~60 minutes.
Now i created a second array that parses the same data but only once a week.
What happens now is that i have an array that is updated every 60 minutes and another that is updated every 7 days.
The reason for this, is that i'm doing a table of teams and i want to check when a team has moved up or down in the standings.
So my first issue is tackled, i have 2 arrays containing the teams one with up to date data and the other with a week old data.
My second issue is how do i compare these objects indexes? each object has many properties, as .name or .teamid
Can someone provide me a sample code on how to compare ArrayA Object.name to ArrayB.name?
Thank you so much.

Answer 1

Your question is confusing; apparently you have written an application which is capable of pulling data from XML files, parsing it, creating an array, and doing all this to a time schedule and yet don't know how to compare two items? It sounds like I'm misunderstanding your question! So here is a guess, maybe it will help:
Cocoa has a pattern for equality of objects - two methods isEqual: and hash work together to provide a standardised way of testing whether two object instances are "equal", whatever that means in terms of what the objects represent.
These methods are provided by all the standard classes, so you can test whether two NSString instances represent the same string etc. For a collection class such as NSArray its isEqual: method compares the elements in the two arrays pairwise by calling their isEqual: methods etc.
The base class, NSObject, provides a default implementation, but as it cannot know what equality means for a particular class its implementation is very basic - two objects are equal if and only if they are exactly the same object, i.e. [a isEqual:a] is YES and nothing else is.
So you need to provide an isEqual: and (this is important) hash pair for your class, which implements what is equality for your class - which is probably defined in terms of some of its properties, such as the name you mention, and will invoke their isEqual: methods.
Of course if equality of your class is simply based on one of its properties, such as name, implementing isEqual: & hash is trivial - the implementations just call the same methods on that property. In this case you don't even need to implement the pair yourself, you can access the property can compare it directly. Something like:
NSUInteger indexOfInterest = ...;
MyClass *objectA = arrayA[indexOfInterest];
MyClass *objectB = arrayB[indexOfInterest];
BOOL itemsAreEqual = [objectA.name isEqual:objectB.name];
If your property is not an object type but some primitive type, such as int, then you just use the standard equality operator:
BOOL itemsAreEqual = objectA.name == objectB.name;
Read: Object Comparison from Apple's Cocoa Core Competencies.