前言
public struct Dictionary : CollectionType, DictionaryLiteralConvertible public class NSDictionary : NSObject, NSCopying, NSMutableCopying, NSSecureCoding, NSFastEnumeration
- 字典用于存储无序的数据元素值，它可以存储任何类型的元素，甚至可以将数组作为字典的元素。
1、Dictionary 与 NSDictionary 的相互转换
- Dictionary 与 NSDictionary 之间可以直接相互转换。Dictionary 转转成 NSDictionary 时，数组中的各项元素被转换为 AnyObject 类型。NSDictionary 转换成 Dictionary 时，数组中的各项元素也被转换为 AnyObject 类型。
let dictinoary:[String:String] = ["key1":"value1", "key2":"value"] // Dictionary 转 NSDictionary // Dictionary 转换成 NSDictionary 型 let nsDictionary1:NSDictionary = dictinoary // Dictionary 转换成 NSDictionary 型 let nsDictionary2:NSDictionary = dictinoary as NSDictionary // NSDictionary 转 Dictionary // NSDictionary 转换成 Dictionary 型 let swiftDictionary1:Dictionary = nsDictionary1 as Dictionary // NSDictionary 转换成 Dictionary 型 let swiftDictionary2:Dictionary = nsDictionary1 as! [String:String]
2、字典的 创建
// Dictionary 型字典 // 创建字典变量，指定数据类型为 Int 型 let dic1 = [String:Int]() // 创建字典变量，Dictionary 等价于 [String:Int] let dic2 = Dictionary () // 创建字典变量，不指定数据类型 let dic3:Dictionary = ["key1":1, "key2":2] // 创建字典变量，指定数据类型为 Int 型 let dic4:Dictionary = ["key1":1, "key2":2, "key3":3] // 创建字典变量，不指定数据类型 let dic5 = ["key1":1, "key2":2, "key3":3, "key4":4] // 创建指定数据类型的字典 let dic6:[String:Int] = ["key1":1, "key2":2, "key3":3, "key4":4] // 创建指定数据类型的字典 let dic7:[String:AnyObject] = ["key1":1, "key2":2, "key3":"value3", "key4":4] // NSDictionary 型字典 let swiftDictionary = ["key1":1, "key2":2, "key3":3, "key4":4] let nsdic1:NSDictionary = swiftDictionary let nsdic2:NSDictionary = swiftDictionary as NSDictionary let nsdic3:NSDictionary = NSDictionary(dictionary: swiftDictionary) let nsdic4:NSDictionary = NSDictionary(dictionary: ["key1":1, "key2":2, "key3":3, "key4":4]) let nsdic5:NSDictionary = NSDictionary(object: "nsdic5", forKey: "key1") let nsdic6:NSDictionary = NSDictionary(objects: ["nsdic6", 2], forKeys: ["key1", "key2"]) let nsdic7:NSDictionary = NSDictionary(dictionaryLiteral: ("key1", "nsdic7"), ("key2", 2), ("key3", 3), ("key4", 4)) // 从 文件 创建字符串 let nsdic8:NSDictionary? = NSDictionary(contentsOfFile: NSHomeDirectory() + "/Desktop/test.txt") // 从 Url 创建字符串 let nsdic9:NSDictionary? = NSDictionary(contentsOfURL: NSURL(fileURLWithPath: NSHomeDirectory() + "/Desktop/test.txt"))
3、字典元素个数的计算
// Dictionary 或 NSDictionary 型字典 let dic = ["key1":1, "key2":2, "key3":3, "key4":4] let num:Int = dic.count
4、通过 key 找对应的 value
// Dictionary 型字典 var dic:Dictionary = ["key1":1, "key2":2, "key3":3, "key4":4] // 获取字典中指定 key 对应的值 let value1 = dic["key2"] // NSDictionary 型字典 let nsDic:NSDictionary = NSDictionary(dictionary: ["key1":1, "key2":2, "key3":3, "key4":4]) // 获取字典中指定 key 对应的值 let value2:AnyObject? = nsDic["key2"] // 获取字典中指定 key 对应的值 let value3:AnyObject? = nsDic.objectForKey("key2") // 获取字典中指定 key 对应的值，key 的值不存在时返回指定的字符串 let value4 = nsDic.objectsForKeys(["key3", "key4", "key5"], notFoundMarker: "not found") 5、通过 value 找对应的 key
// NSDictionary 型字典 let nsDic:NSDictionary = NSDictionary(dictionary: ["key1":1, "key2":3, "key3":3, "key4":4]) let keys:AnyObject = nsDic.allKeysForObject(3)
6、字典中所有 key 的获取
// Dictionary 型字典 let dic:Dictionary = ["key1":1, "key2":2, "key3":3, "key4":4] let keys1 = dic.keys // NSDictionary 型字典 let nsDic:NSDictionary = NSDictionary(dictionary: ["key1":1, "key2":2, "key3":3, "key4":4]) let keys2 = nsDic.allKeys
7、字典中所有 value 的获取
// Dictionary 型字典 let dic:Dictionary = ["key1":1, "key2":2, "key3":3, "key4":4] let values1 = dic.values // NSDictionary 型字典 let nsDic:NSDictionary = NSDictionary(dictionary: ["key1":1, "key2":2, "key3":3, "key4":4]) let values2 = nsDic.allValues
8、字典键值对的 追加
// Dictionary 型字典 var dic:Dictionary = ["key1":1, "key2":2, "key3":3, "key4":4] // key 不存在时，追加键值对（key 值为新增的，若 key 值已存在则为修改对应的 value 值） dic["key5"] = 5 // NSDictionary 型字典 let nsDic:NSMutableDictionary = NSMutableDictionary(dictionary: ["key1":1, "key2":2, "key3":3, "key4":4]) // key 不存在时，追加键值对（key 值为新增的，若 key 值已存在则为修改对应的 value 值） nsDic["key5"] = 5 // 向字典末尾追加一个字典 nsDic.addEntriesFromDictionary(["key6":6, "key7":7])
9、字典键值对的 修改
// Dictionary 型字典 var dic:Dictionary = ["key1":1, "key2":2, "key3":3, "key4":4] // key 存在时，修改其值 dic["key4"] = 100 // 修改指定的 key 对应的值 dic.updateValue(44, forKey: "key4") // NSDictionary 型字典 let nsDic:NSMutableDictionary = NSMutableDictionary(dictionary: ["key1":1, "key2":2, "key3":3, "key4":4]) // key 存在时，修改其值 nsDic["key3"] = 33 // 修改指定的 key 对应的值 nsDic.setObject(100, forKey: "key4") // 修改整个字典 nsDic.setDictionary(["key6":6, "key7":7])
10、字典键值对的 删除
// Dictionary 型字典 var dic:Dictionary = ["key1":1, "key2":2, "key3":3, "key4":4] // 删除指定 key 对应的值 dic.removeValueForKey("key2") // 删除字典的所有元素 dic.removeAll(keepCapacity: true) // NSDictionary 型字典 let nsDic:NSMutableDictionary = NSMutableDictionary(dictionary: ["key1":1, "key2":2, "key3":3, "key4":4]) // 删除指定 key 对应的值 nsDic.removeObjectForKey("key2") // 删除指定 key 对应的值 nsDic.removeObjectsForKeys(["key1", "key4"]) // 删除字典的所有元素 nsDic.removeAllObjects() 11、字典遍历
// NSDictionary 型字典 let nsDic:NSDictionary = NSDictionary(dictionary: ["key1":1, "key2":2, "key3":3, "key4":4]) // for...in 循环 // 遍历出的为 key-value 的元组, key 不需要可以用 _ 替代 for (_, obj) in nsDic { print(obj) } // 闭包遍历 nsDic.enumerateKeysAndObjectsUsingBlock { (key:AnyObject, obj:AnyObject, stop:UnsafeMutablePointer ) in print(obj) } // 迭代器遍历 // key 迭代器 let keyEnu:NSEnumerator = nsDic.keyEnumerator() while let key:AnyObject = keyEnu.nextObject() { print(nsDic.objectForKey(key)) } // 对象迭代器 let objEnu:NSEnumerator = nsDic.objectEnumerator() while let obj:AnyObject = objEnu.nextObject() { print(obj) } 12、字典排序
// NSDictionary 型字典 let nsDic:NSDictionary = NSDictionary(dictionary: ["key1":"value1", "key2":"value2", "key3":"value3", "key4":"value4"]) // 用闭包排序 let keys1 = nsDic.keysSortedByValueUsingComparator { (obj1:AnyObject, obj2:AnyObject) -> NSComparisonResult in return (obj1 as! String).compare(obj2 as! String) } for key in keys1 { print(nsDic.objectForKey(key)) } // 用指定的方法排序 let keys2 = nsDic.keysSortedByValueUsingSelector(#selector(NSNumber.compare(_:))) for key in keys2 { print(nsDic.objectForKey(key)) }