The use of OC base variable dictionaries and immutable dictionaries

The use of OC base mutable dictionaries with immutable dictionaries 1. Immutable dictionaries

1.1 Creating an immutable dictionary

        //Create a dictionary//Note://1, the number of elements is even//2, each of the two elements is a key-value pair//3, value in front, key in rearNsdictionary *dic = [[Nsdictionary alloc] Initwithobjectsandkeys:@"Huang",@"name",@" -",@" Age", nil]; NSLog (@"%@", DIC); //use a dictionary to create another dictionaryNsdictionary *dic2 =[[Nsdictionary alloc] initwithdictionary:dic]; //Note://the number of 1,value and keys must be the same//The order of the elements within the 2,values and keys correspondsNsdictionary *dic3 = [[Nsdictionary alloc] Initwithobjects:[nsarray arraywithobjects:@"Huang",@" -", nil] Forkeys:[nsarray arraywithobjects:@"name",@" Age", Nil]]; NSLog (@"%@", DIC3); //new ways to create arraysNsarray *arr = @[@"1",@"2",@"3"]; Nsdictionary*DIC4 = [Nsdictionary Dictionarywithobjectsandkeys:@" -",@" Age",@"Huang",@"name", nil]; Nsdictionary*DIC5 =[Nsdictionary DICTIONARYWITHDICTIONARY:DIC4]; Nsdictionary*DIC6 = [Nsdictionary dictionarywithobjects:@[@"Huang",@" -"] Forkeys:@[@"name",@" Age"]]; //new ways to create dictionariesNsdictionary *dic7 = @{@"name":@"Huang",@" Age":@" -"};

1.2 Common operations for immutable dictionaries

        //common operations for dictionariesNsinteger count =[Dic7 Count]; NSLog (@"%ld", Count); //to get a value by keyNSString *str = [Dic7 valueforkey:@"name"]; NSLog (@"%@", str); //get all the keysNsarray *allkeys =[Dic7 AllKeys]; NSLog (@"%@", AllKeys); //get all the valueNsarray *allvalues =[Dic7 allvalues]; //gets a value corresponding to the keyNsdictionary *dic8 = @{@"name":@"Huang",@" Age":@" the",@"score":@" the"}; Nsarray*ARR1 = [Dic8 allkeysforobject:@" the"]; NSLog (@"%@", arr1); Nsdictionary*DIC9 = @{@"Dic8":d Ic8,@"Dic7":d Ic7}; NSLog (@"%@", DIC9); //nesting of arrays and dictionariesNsarray*array1 = @[@"1",@"2",@"3"]; Nsdictionary*dictionary1 = @{@"name":@"xiaoming",@" Age":@"Ten"}; Nsdictionary*dictionary2 = @{@"Array": Array1,@"Dictionary":d Ictionary1}; NSLog (@"%@", Dictionary2); Nsarray*array2 =@[array1,dictionary1]; NSLog (@"%@", array2); //the traversal of a dictionaryNsdictionary *dictionary3 = @{@"name":@"Huang",@" Age":@" -",@" Number":@" -"}; Nsarray*ALLKEYS1 =[Dictionary3 AllKeys];  for(NSString *keyinchallKeys1) {NSString*str =[Dictionary3 Objectforkey:key]; NSLog (@"%@=%@", KEY,STR); }

2. Variable Dictionaries

2.1 Creation and use of variable dictionaries

Nsdictionary *dic = @{@"name":@"xiaoming",@" Age":@"Ten"}; Nsdictionary*dic1 = @{@" Age":@" the",@"score":@" -"}; Nsmutabledictionary*mudic =[[Nsmutabledictionary alloc] init]; //add elements from a dictionary to a mutable dictionary//Note://when DIC has the same key as a mutable dictionary, the key is not added, but the value corresponding to the key is overwritten. [Mudic Addentriesfromdictionary:dic]; NSLog (@"%@", Mudic);        [Mudic Addentriesfromdictionary:dic1]; NSLog (@"%@", Mudic); //Add an element//Note://1,setobject:forkey: Adds an element when key is not present and modifies the element value when key is present[Mudic SetObject:@"mingming"Forkey:@"Nickname"]; [Mudic setobject:@"Xiaohua"Forkey:@"name"]; NSLog (@"%@", Mudic); //Delete an element[Mudic Removeobjectforkey:@"name"]; NSLog (@"%@", Mudic); //Delete all elements of the keys array[Mudic removeobjectsforkeys:@[@"Nickname",@"AAA"]]; NSLog (@"%@", Mudic); //Delete all elements within a dictionary[Mudic removeallobjects]; NSLog (@"%@", Mudic); //Modify Dictionary[Mudic Setdictionary:dic]; NSLog (@"%@", mudic);

The use of OC base variable dictionaries and immutable dictionaries