斯威夫特NSPredicate，名字和姓NSCompoundPredicate？

Question

在下面的代码中，我特别使用NSPredicates，我使用NSCompoundPredicate检查搜索函数中的多个不同参数。如何使用我目前正在使用的名字和姓氏进行搜索，但是它不会返回我的UITableView中的任何内容。我在复合谓词中列出的所有其他谓词都非常有用。

func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {

textInSearchField = searchBar.text!

if searchBar.text == ""{

  print("Searching for all clients.")
  retrieveClients()
  view.endEditing(true)
  clientTableView.reloadData()

}else{

  print("Enter a client name to search.")
  isFilteringSearch = true

  let appDelegate = UIApplication.shared.delegate as! AppDelegate
  let context = appDelegate.persistentContainer.viewContext

  let firstAndLast = NSPredicate(format: "firstName = %@ AND lastName = %@", textInSearchField)
  let firstNamePredicate = NSPredicate(format: "firstName = %@", textInSearchField)
  let lastNamePredicate = NSPredicate(format: "lastName = %@", textInSearchField)
  let idPredicate = NSPredicate(format: "id = %@", textInSearchField)
  let orPredicate = NSCompoundPredicate(type: NSCompoundPredicate.LogicalType.or, subpredicates: [firstAndLast,firstNamePredicate, lastNamePredicate, idPredicate])

  clientsEntity.predicate = orPredicate

  clients = try! context.fetch(clientsEntity) as! [NSManagedObject]
  view.endEditing(true)
  clientTableView.reloadData()

}

}

要记住的一点是，我仍然需要能够使用LogicalType.or，因为我希望用户可以选择按名、姓进行搜索，但同时也需要同时使用Harold 或Finch/Harold等。

干杯!

Answer 1

let firstAndLast = NSPredicate(format: "firstName = %@ AND lastName = %@", textInSearchField)
let firstNamePredicate = NSPredicate(format: "firstName = %@", textInSearchField)
let lastNamePredicate = NSPredicate(format: "lastName = %@", textInSearchField)
let idPredicate = NSPredicate(format: "id = %@", textInSearchField)

let orPredicate = NSCompoundPredicate(type: NSCompoundPredicate.LogicalType.or, subpredicates: [firstAndLast,firstNamePredicate, lastNamePredicate, idPredicate])

我希望对orPredicate来说，它应该是[firstAndLast, idPredicate]，但是您没有让它工作。否则，您需要重新考虑，这是您的orPredicate当前逻辑：

if ((a == x AND b == x) OR (a == x) OR (b == x) OR (c = x)) {
}

(a == x AND b == x)是无用的。

这方面有一个问题：

let firstAndLast = NSPredicate(format: "firstName = %@ AND lastName = %@", textInSearchField)

您有两个占位符(%@)，但只有一个参数(textInSearchField)。

let firstAndLast = NSPredicate(format: "firstName = %@ AND lastName = %@", textInSearchField, textInSearchField)

Answer 2

感谢您的帮助，我最终使用了带有的另一种方法--我的代码如下所示，用于任何需要类似函数帮助的人，您可以通过字符(这适用于所有字符串，即名称或姓氏)进行搜索--在我的示例中，ID也是作为字符串存储的。

func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {

textInSearchField = searchBar.text!

if searchBar.text == ""{

  retrieveClients()
  view.endEditing(true)
  clientTableView.reloadData()

}else{

  isFilteringSearch = true
  let appDelegate = UIApplication.shared.delegate as! AppDelegate
  let context = appDelegate.persistentContainer.viewContext
  let words = textInSearchField.components(separatedBy: " ")

  for word in words{

    if (word).count == 0{
      continue
    }

  let firstNamePredicate = NSPredicate(format: "firstName contains[c] %@", word)
  let lastNamePredicate = NSPredicate(format: "lastName contains[c] %@", word)
  let idPredicate = NSPredicate(format: "id contains[c] %@", word)
  let orPredicate = NSCompoundPredicate(type: NSCompoundPredicate.LogicalType.or, subpredicates: [firstNamePredicate, lastNamePredicate, idPredicate])
  clientsEntity.predicate = orPredicate

  }

  clients = try! context.fetch(clientsEntity) as! [NSManagedObject]
  view.endEditing(true)
  clientTableView.reloadData()

}

}

我在这篇文章NSPredicate: Combine CONTAINS with IN上遵循了第二个答案

谢谢