IOS Intro-nsdictionary and Nsmutabledictionary

Basic usage of nsdictionary and nsmutabledictionary

1. Immutable Dictionary Nsdictionary

Dictionary initialization

NSNumber *numobj = [NSNumber numberwithint:100];

Class with an element.

Nsdictionary *dic = [nsdictionary dictionarywithobject:numobj forkey:@ "key"];

Initialize two elements

Nsdictionary *dic = [nsdictionary dictionarywithobjectsandkeys:numobj, @ "Valuekey", NumObj2, @ "value2", nil];

Initializes a new dictionary with a new dictionary containing otherdic

Nsdictionary *dic = [Nsdictionary dictionarywithdictionary:otherdic];

Initializing a dictionary with the contents of a file

Nsdictionary *dic = [Nsdictionary Dictionarywithcontentsoffile:path];

Common methods

Get Dictionary number

Nsinteger count = [dic count];

Get the corresponding value object by key

NSObject *valueobj = [dic objectforkey:@ "key"];

Converts the dictionary key to an enumeration object that iterates through the

Nsenumerator *enumerator = [dic keyenumerator];

Gets the collection of all keys

Nsarray *keys = [dic AllKeys];

Get a collection of all values

Nsarray *values = [dic allvalues];

2. Variable array nsmutabledictionary

Initialize an empty mutable dictionary

Nsmutabledictionary *dic2 = [nsmutabledictionary dictionarywithobjectsandkeys:@ "v1", @ "Key1", @ "V2", @ "Key2", nil];

Nsdictionary *dic3 = [nsdictionary dictionarywithobject:@ "v3" forkey:@ "Key3"];

To add an entire Dictionary object to a dictionary 2 object 3

[Dic2 ADDENTRIESFROMDICTIONARY:DIC3];

One of the best new Key3 and Value3 to the Dictionary 2 object

[Dic2 setvalue:@ "Value3" forkey:@ "Key3"];

Initialize an empty mutable dictionary

Nsmutabledictionary *dic1 = [Nsmutabledictionary dictionary];

The empty Dictionary 1 object content setting is the same as the Dictionary 2 object

[Dic1 Setdictionary:dic2];

Delete the corresponding value of key1 in the dictionary

[DIC1 [email protected] "Key1"];

Nsarray *array = [Nsarray arraywithobjects:@ "Key1", nil];

Removes the contents of the dictionary 1 based on the specified array (key)

[Dic2 Removeobjectsforkeys:array];

Remove all objects from a dictionary

[Dic1 removeallobjects];

Traverse Dictionary

Quick Enumeration

For (ID key in dic) {

ID obj = [dic objectforkey:key];

NSLog (@ "%@", obj);

}

General enumeration

Nsarray *keys = [dic AllKeys];

INR length = [keys count];

for (int i = 0; i < length;i++) {

ID key = [keys objectatindex:i];

ID obj = [dic objectforkey:key];

NSLog (@ "%@", obj);

}

Enumeration by enumeration type

Nsenumerator *enumerator = [dic keyenumerator];

ID key = [enumerator nextobject];

while (key) {

ID obj = [dic objectforkey:key];

NSLog (@ "%@", obj);

key = [Enumerator nextobject];

}

IOS Intro-nsdictionary and Nsmutabledictionary