如何使用对象属性的谓词过滤NSArray [英] How to filter NSArray using predicate on an object property

问题描述

-(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 和 filteredArray 是 NSArray s。

hotelArray 的对象类型为 hotel 其中 hotel 有一个属性姓名。

hotelArray has objects of type hotel where hotel has a property name.

问题：
我想过滤 hotelArray 根据到 hotel.name 当 hotel.name 匹配在 searchText中输入的文字 [text field]，但我得到一个空的 self.filteredArray 。

Problem : I want to filter hotelArray according to hotel.name when hotel.name matches text entered in searchText [text field], but I am getting an empty self.filteredArray.

推荐答案

尝试以下行，并确保 properyName 区分大小写。并且你已经以谓词格式放置了，，这就是为什么它无法正常工作。只需用以下代码替换您的代码。

Try following lines, and make sure properyName is case sensitive. and you have placed , in predicate format, thats why its not working. just replace your code with following.

目标C

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

Swift

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 过滤器

Using 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)")

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