ios - What is the most reliable and fastest type or data structure to store data using Objective C? -

i looking type or data structure store big number of same type primitives on app (mac os x or ios) using objective c. understood nsnumber stores 1 primitive (correct me if wrong). have, let's say, thousands of integers or strings. which best solution put, store , access them there? nsset, nsarray, nsmutablearray, nsdictionary, nsmutabledictionary or else? know have different features, care performance of basic operations (putting, storing, retrieving).

it depends on how want add, store , remove data.

first let go through each type of data structure available in objective-c:

primitive array

this basic type of storage in objective-c(or c) used store primitives. ex: int a[4] = {1, 2, 3, 4}; limitation

• can store primitive types.
• array size cannot changed once declared.
• can retrieved index.
• can store single type of data, defined @ time of declaring array.

nsarray

this container storing objects. object of type nsobject (or inherits nsobject) or of type 'id' can stored in nsarray.

• once initialized, cannot mutated i.e. array size cannot changed nor objects contains can modified. in terms of security.
• objects can accessed index.

nsmutablearray

same nsarray, but

• can mutated, i.e. existing objects can modified , new objects can added or deleted.

nsset

same nsarray but

• stores unique objects.
• objects cannot accessed index. objects can accessed enumeration.

nsmutableset

same nsset, but

• can mutated, i.e. objects can added or removed @ later point of time.

nsorderedset

same nsarray, i.e. objects stored , retrieved index, but

• stores unique objects.

nsmutableorderedset

same nsmutablearray, but

• stores unique objects.

nsdictionary

can store type of data.

• objects stored , retrieved key.
• once initialized, cannot mutated i.e. cannot add new key-values nor can update existing objects associated particular key.

nsmutabledictionary

same nsdictionary

• can mutated, i.e. new objects can added or removed , existing objects can modified.

this short description used data structures in objective-c. these used based on need of program , how data manipulated.

therefore,

• if want store thousands of numbers , strings , want access index value use nsmutablearray. if not going add, remove or modify objects in future use nsarray.
• if want store data not want duplicates , want access index use nsorderedset/nsmutableorderedset
• if want store data not want duplicates , order doesn't matter use nsset/nsmutableset.
• if want access data particular key use nsdictionary/nsmutabledictionary

regarding performance

• since nsset doesn't contain order, more performant nsarray

• here , detailed article on performance characteristics each data structure discussed above

  class                      time [ms]    1,000,000 elements 

  adding

  nsmutableorderedset         3190.52 nsmutabledictionary         2522.47 nsmutableset                2511.96 nsmutablearray              1423.26 nsset                          8.03 

  random access

  nsmutableorderedset           10.74 nsmutabledictionary            9.18 nsmutablearray                 8.08 nsmutableset                   4.47 nsset                          3.56 

to know more objective-c data types , data structure, read this