如何使用对象属性的谓词过滤NSArray

Question

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
  [self.map removeAnnotations:self.map.annotations];
  if ([textField isEqual:self.searchText]) {
      NSPredicate *bPredicate = 
      [NSPredicate predicateWithFormat:@"name contains[c],  %@",self.searchText.text];

      self.filteredArray = [self.hotelArray filteredArrayUsingPredicate:bPredicate];
      NSLog(@" HEARE %@",self.filteredArray);
      [self markAllHotels];
  }
  return YES;
}

hotelArray并且filteredArray是NSArray.

hotelArray有一个类型的对象hotel,其中hotel有一个属性name.

问题:我想筛选hotelArray根据hotel.name时hotel.name中输入匹配的文本searchText[文本字段],但我得到一个空self.filteredArray.

Answer 1

尝试以下行,并确保properyName区分大小写.你已经置于,谓词格式,这就是为什么它不起作用.只需用以下代码替换您的代码.

目标C.

NSPredicate *bPredicate = [NSPredicate predicateWithFormat:@"SELF.name contains[cd] %@",self.searchText.text];
self.filteredArray = [self.hotelArray filteredArrayUsingPredicate:bPredicate];
NSLog(@"HERE %@",self.filteredArray);

迅速

var bPredicate: NSPredicate = NSPredicate(format: "SELF.name contains[cd] %@", self.searchText.text)
self.filteredArray = self.hotelArray.filteredArrayUsingPredicate(bPredicate)
NSLog("HERE %@", self.filteredArray)

使用swift filter

var searchText = "Galaxy"

let filteredArray = hotelArray.filter { $0["name"] == searchText }
print("** Result ** \n\(filteredArray)")

Swift 3.0

let arrEmp = [["name": "James", "age" : 27, "city" : "New york"],
                   ["name": "Johnson", "age" : 24, "city" : "London"],
                   ["name": "Alex", "age" : 28, "city" : "Newark"],
                   ["name": "Mark", "age" : 25, "city" : "Paris"],
                   ["name": "Steve", "age" : 25, "city" : "Silicon Valley"],
                   ["name": "Lary", "age" : 28, "city" : "New york"]]

// *** Filter by Name exact match ***
var filterByName = arrEmp.filter { $0["name"] == "Mark" }
print("filterByName \(filterByName)")

// *** Filter by Age ***
var filterByAge = arrEmp.filter { $0["age"] as! Int >  25 }
print("filterByAge \(filterByAge)")

Swift 4.0

var filterByName = arrEmp.filter
do {
    $0["name"] == "Mark"
}
print("filterByName filterByName)")

var filterByAge = arrEmp.filter
do {
    $0["age"] as! Int > 25
}
print("filterByAge filterByAge)")

Answer 2

根据您的信息,这是您的情况:

self.hotelArray      // Array in which we perform a search
self.filteredArray   // Result array
name                 // Property of the object used for the predicate

这个谓词应该适合你:

NSString *searchText = self.searchText.text;
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"self.name contains[c] %@", searchText];
self.filteredArray = [self.hotelArray filteredArrayUsingPredicate:predicate];