Introduction

This document describes objects that let you group together other types of objects in arrays, sets, or dictionaries.

All developers using Cocoa need to understand how collections work.

Organization of This Document

The various types of collection and the operations you can perform on them are discussed in the following articles:

• ‚ÄúArrays: Ordered Collections‚Äù

• ‚ÄúDictionaries: Collections of Keys and Values‚Äù

• ‚ÄúSets: Unordered Collections of Objects‚Äù

• ‚ÄúCounted Sets: Unordered Collection of Indistinct Objects‚Äù

• ‚ÄúSorting and Filtering NSArray Objects‚Äù

• ‚ÄúEnumeration: Traversing a Collection‚Äôs Elements‚Äù

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