使用NSExpressions和NSPredicates搜索联系人

Question

我已经能够通过联系人的名字，姓氏，公司和备注来过滤联系人表格。但是，我还需要能够在联系人的邮政地址中搜索搜索字词。有没有人以前使用过NSEpression / NSPredicate方法，而不是简单地循环访问联系人？

我有超过6000个联系人要经历这样的循环并不是非常有效。我已经开始尝试解决这个问题了，但我却失败了。我一直收到以下错误：由于未捕获的异常终止应用程序＆＃39; NSUnknownKeyException＆＃39;，原因：＆＃39; [valueForUndefinedKey：]：此类不是关键城市的键值编码兼容。 ＆＃39; ，但我知道我在提取联系人时提供了描述符。再次，我们非常感谢您的帮助，并且我已在下面粘贴了我的代码。

func updateSearchResults(for searchController: UISearchController) {
    // Update the filtered array based on the search text.
    let searchResults = contacts

    // Strip out all the leading and trailing spaces.
    let whitespaceCharacterSet = CharacterSet.whitespaces
    let strippedString = searchController.searchBar.text!.trimmingCharacters(in: whitespaceCharacterSet)
    let searchItems = strippedString.components(separatedBy: " ") as [String]

    // Build all the "AND" expressions for each value in the searchString.
    let andMatchPredicates: [NSPredicate] = searchItems.map { searchString in
        var searchItemsPredicate = [NSPredicate]()

        // Key Path field matching.
        let firstNameExpression = NSExpression(forKeyPath: CNContactGivenNameKey)
        let lastNameExpression = NSExpression(forKeyPath: CNContactFamilyNameKey)
        let companyNameExpression = NSExpression(forKeyPath: CNContactOrganizationNameKey)
        let noteExpression = NSExpression(forKeyPath: CNContactNoteKey)
        //let addressesExpressions = NSExpression(forKeyPath: CNPostalAddressCityKey)

        var searchStringExpression: NSExpression!
        if searchString == "$" || searchString == "$$" {
            searchStringExpression = NSExpression(forConstantValue: "customer")
        } else {
            searchStringExpression = NSExpression(forConstantValue: searchString)
        }

        let firstNameSearchComparisonPredicate = NSComparisonPredicate(leftExpression: firstNameExpression, rightExpression: searchStringExpression, modifier: .direct, type: .contains, options: .caseInsensitive)
        let lastNameSearchComparisonPredicate = NSComparisonPredicate(leftExpression: lastNameExpression, rightExpression: searchStringExpression, modifier: .direct, type: .contains, options: .caseInsensitive)
        let companyNameSearchComparisonPredicate = NSComparisonPredicate(leftExpression: companyNameExpression, rightExpression: searchStringExpression, modifier: .direct, type: .contains, options: .caseInsensitive)
        let noteSearchComparisonPredicate = NSComparisonPredicate(leftExpression: noteExpression, rightExpression: searchStringExpression, modifier: .direct, type: .contains, options: .caseInsensitive)
        //let addressesSearchComparisonPredicate = NSComparisonPredicate(leftExpression: addressesExpressions, rightExpression: searchStringExpression, modifier: .direct, type: .contains, options: .caseInsensitive)

        searchItemsPredicate.append(firstNameSearchComparisonPredicate)
        searchItemsPredicate.append(lastNameSearchComparisonPredicate)
        searchItemsPredicate.append(companyNameSearchComparisonPredicate)
        searchItemsPredicate.append(noteSearchComparisonPredicate)
        //searchItemsPredicate.append(addressesSearchComparisonPredicate)

        // Add this OR predicate to our master AND predicate.
        let orMatchPredicate = NSCompoundPredicate(orPredicateWithSubpredicates:searchItemsPredicate)

        return orMatchPredicate
    }

    // Match up the fields of the Product object.
    let finalCompoundPredicate = NSCompoundPredicate(andPredicateWithSubpredicates: andMatchPredicates)
    let filteredResults = searchResults.filter { finalCompoundPredicate.evaluate(with: $0) }

    // Hand over the filtered results to our search results table.
    self.filteredContacts = filteredResults
    self.tableView.reloadData()
}