厚积薄发,滴水穿石

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数据加载中……

NSDictionary

The NSDictionary class declares the programmatic interface to objects that manage immutable associations of keys and values.NSDictionary
类定义了对于objects的接口,用于将键值和数值关联起来。
Use this class or its subclassNSMutableDictionary when you need a convenient and efficient way to retrieve data associated with an arbitrary key.
用此类或者它的子类,你可以方便高效的通过任意键值来检索数据。
Within a dictionary, the keys are unique.
在一个字典中,键是唯一的。
In general, a key can be any object  (provided that it conforms to the NSCopying protocol—see below), but note that when using key-value coding the key must be a string (see “Key-Value Coding Fundamentals”). Neither a key nor a value can be nil; if you need to represent a null value in a dictionary, you should use NSNull.
通常,键可以是任何遵循NSCopying协议的对象,但是通常是一个string,键值和数据必须不为nil,如果想表示一个空的值,则用NSNull。

Tasks

Creating a Dictionary


Initializing an NSDictionary Instance


Counting Entries


Comparing Dictionaries


Accessing Keys and Values


Enumerating Dictionaries


Sorting Dictionaries


Filtering Dictionaries


Storing Dictionaries


Accessing File Attributes


Creating a Description

posted on 2012-02-04 22:16 Wangkeke 阅读(6712) 评论(0)  编辑 收藏 引用 所属分类: IOS


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