使用NSPredicate的Swift过滤器数组 [英] Swift filter array using NSPredicate

问题描述

我有一个用Swift编写的应用程序，它从地址簿中提取用户联系人。

I have an application written in Swift that is pulling in the users contacts from their address book.

我想过滤掉只包含公司名称的联系人（以便让您假设真人联系而不是商家）

I want to filter out the contact that only contain a company name (so that you get your "assumed" real person contact and not businesses)

以下是我在app的Objective-C版本中实现的目标：

Here is how this is being accomplish in the Objective-C version of my app:

NSArray *allContacts = (__bridge_transfer NSArray *)ABAddressBookCopyArrayOfAllPeople(addressBook);

NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(id person, NSDictionary *bindings) {
    NSString *firstName = CFBridgingRelease(ABRecordCopyValue((__bridge ABRecordRef)person, kABPersonFirstNameProperty));
    NSString *lastName  = CFBridgingRelease(ABRecordCopyValue((__bridge ABRecordRef)person, kABPersonLastNameProperty));

    return (firstName || lastName);
}];

NSArray *peopleNotCompanies = [allContacts filteredArrayUsingPredicate:predicate];

这很有效，所以这是我尝试在Swift中做到这一点：

This works perfectly, so here is my attempt to do this in Swift:

var contactList: NSArray = ABAddressBookCopyArrayOfAllPeople(addressBook).takeRetainedValue()

var predicate: NSPredicate = NSPredicate { (AnyObject person, NSDictionary bindings) -> Bool in
    var firstName: String = ABRecordCopyValue(person as ABRecordRef, kABPersonFirstNameProperty).takeRetainedValue() as String
    var lastName: String = ABRecordCopyValue(person as ABRecordRef, kABPersonLastNameProperty).takeRetainedValue() as String

    return firstName || lastName
})

现在这有几个问题。我在return语句和谓词调用结束时收到这些错误：

Now this has a couple problems. I am getting these errors on the return statement and the end of the predicate call:

如何在Swift的ObjC代码中提供类似的功能？或者有更好的方法在swift中检查联系人是否只有公司名称，然后从最终数组中省略它？

How can I provide similar functionality found in my ObjC code in Swift? Or is there a better way in swift to check if a contact has ONLY a company name and then omit it from the final array?

谢谢！

推荐答案

如果firstName和lastName是可选字符串，则可以将它们与nil进行比较，并在布尔表达式中使用它们。

If you have firstName and lastName be optional strings, you can compare them against nil and use them in a boolean expression.

您的第二个错误是由于关闭后的额外费用。这段代码应该有效。

Your second error is due to the extra paren after your closure. This code should work.

var predicate: NSPredicate = NSPredicate { (AnyObject person, NSDictionary bindings) -> Bool in
    var firstName: String? = ABRecordCopyValue(person as ABRecordRef, kABPersonFirstNameProperty).takeRetainedValue() as? String
    var lastName: String? = ABRecordCopyValue(person as ABRecordRef, kABPersonLastNameProperty).takeRetainedValue() as? String

    return firstName != nil || lastName != nil
}

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