iOS - Comparing 2 Arrays and Objects in an array - Logic Issue

问题

I have an NSArray which contains Person objects.

This person object contains the following;

> Name 
> Age 
> School 
> Address 
> Telephone_Number

Later on i will be setting values to this person object, like person.Name=@"Jemmy"; (but i will not be setting other attributes, Age, School etc.).

I have an NSArray called personArray, and it contains 1000 person object records in it. Now i need to Filter out all the objects that contains the Name Jemmy. How can i do this ?

What i was thinking of doing is;

NSMutableArray *arrayThatContainAllPersonObjects = [NSMutableArray arrayWithArray:personArray];
[arrayThatContainAllPersonObjects removeObjectsInArray:arrayWeAddedTheName];

But, what i will get is, an array that doesn't have my filter results. Anyway this might not be the correct approach. I believe we could use NSSets, UNIONS to solve this.

note:Some might say that this is a duplicate question, but i have searched so much on this.

回答1:

You want to use an NSPredicate with NSArray's filteredArrayUsingPredicate. Something like this:

NSArray *filteredArray = [personArray filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"name = \"Jemmy\""]];

回答2:

If the Jemmy's are all identical the easy option is

  NSArray * cleanArray = [arrayWithAll removeObjectIdenticalTo:jemmyPerson];

If that is not the case (they are called Jemmy - but have different schools or whatever) you are down to

   NSArray * cleanArray = [arrayWithAll filterUsingPredicate:jemmyPredicate];

or similar with a block/iteration. The predicate can be constructed with something like:

   NSPredicate jemmyPredicate = [NSPredicate predicateWithFormat:@"name == \"jemmy\"];

    NSPredicate jemmyPredicate = [NSPredicate predicateWithBlock:^(id evaluatedObject, NSDictionary *bindings){
           return [evaluatedObject.Name isEqual:@"Jemmy"];
    }];

consult the predicate page for more details.

回答3:

Try using NSArray's filteredArrayUsingPredicate: function and write a custom predicate to evaluate the objects in your array.

来源：https://stackoverflow.com/questions/9178585/ios-comparing-2-arrays-and-objects-in-an-array-logic-issue

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objective-c

iphone

nsset