IOS字典NSDictionary與NSMutableDictionary知識(shí)點(diǎn)

2019-11-14 18:40:30

字體：大中小

供稿：網(wǎng)友

字典中的元素是以鍵值對(duì)的形式存儲(chǔ)的,鍵值對(duì)的鍵和值，都是任意的對(duì)象，但是鍵往往使用字符串,字典存儲(chǔ)對(duì)象的地址沒(méi)有順序,字典的遍歷分為：鍵的遍歷和值的遍歷,字典與數(shù)組的區(qū)別：數(shù)組講究順序，而字典可以快速幫助我們找到數(shù)據(jù)，數(shù)據(jù)是我們的目的，鍵是我們的手段;其中NSMutableDictionary是NSDictionary的子類，所以其擁有NSDictionary所有的功能；主要是一些常見(jiàn)的操作，別外一些操作見(jiàn)其相應(yīng)的文檔，下面的代碼部分還運(yùn)用的第三方插件BlocksKit相結(jié)合；

a:NSDictionary是由鍵值對(duì)(key-value)組成的數(shù)據(jù)集合
b:鍵:可以是任何對(duì)象 (通常是NSString類型的對(duì)象)，同時(shí)鍵必須是單值
c:值:可以是任何對(duì)象，不能為nil
d:常用方式：我們根據(jù)鍵來(lái)查找相應(yīng)值
e:字典有可變的和不可變的,可變的字典中可動(dòng)態(tài)的添加和刪除元素
f:和數(shù)組不同，字典是無(wú)序的

1:NSDictionary一些常見(jiàn)的操作

//創(chuàng)建詞典    NSDictionary *dictionary=[NSDictionary dictionaryWithObjectsAndKeys:@"wujy",@"name",@29,@"age",nil];    NSInteger Count=[dictionary count];    NSLog(@"詞典的個(gè)數(shù)為%ld",Count);        //得到詞典中的所有key    NSEnumerator *enumeratorkey=[dictionary keyEnumerator];    for (NSObject *obj in enumeratorkey) {        NSLog(@"key為：%@",obj);        NSLog(@"通過(guò)key找到value值為：%@",[dictionary objectForKey:obj]);    }        //得到詞典中的所有value值    NSEnumerator *enumeratorvalue=[dictionary objectEnumerator];    for (NSObject *obj in enumeratorvalue) {        NSLog(@"value為：%@",obj);    }        //簡(jiǎn)便的方式創(chuàng)建 key排前面value排后面    NSDictionary *newDictionary=@{@"name":@"wujy",@"age":@29};    NSArray *keyArray=[newDictionary allKeys];    for (NSObject *obj in keyArray) {        NSLog(@"key的值為：%@",obj);    }        NSArray *valueArray=[newDictionary allValues];    for (NSObject *obj in valueArray) {        NSLog(@"value的值為：%@",obj);    }        //blocks插件    NSDictionary *blockDictionary=[NSDictionary dictionaryWithObjects:[[NSArray alloc] initWithObjects:@3,@15,@29,nil] forKeys:[[NSArray alloc] initWithObjects:@"IOS",@"work",@"age",nil]];    //遍歷    [blockDictionary bk_each:^(id key, id obj) {        NSLog(@"使用blocks的key為:%@",key);        NSLog(@"對(duì)應(yīng)的value為:%@",obj);    }];        //過(guò)濾 只在第一個(gè)符合條件時(shí)就停止

    NSDictionary *matchDictionary=[blockDictionary bk_match:^BOOL(id key, id obj) {

        BOOL select=[obj intValue]<10?YES:NO;        return select;    }];    NSLog(@"match符合的項(xiàng)為：%@",matchDictionary);        //過(guò)濾    NSDictionary *selectDictionary=[blockDictionary bk_select:^BOOL(id key, id obj) {        BOOL select=[obj intValue]>10?YES:NO;        return select;    }];    NSLog(@"select符合的項(xiàng)為%@",selectDictionary);        //反向過(guò)濾    NSDictionary *rejectDictionary=[blockDictionary bk_reject:^BOOL(id key, id obj) {        BOOL select=[obj intValue]>10?YES:NO;        return select;    }];    NSLog(@"reject符合的項(xiàng)為%@",rejectDictionary);        //對(duì)各個(gè)項(xiàng)進(jìn)行修改    NSDictionary *mapDictinary=[blockDictionary bk_map:^id(id key, id obj) {        return [NSNumber numberWithInt:[obj intValue]+1];    }];    NSLog(@"map修改后的項(xiàng)為%@",mapDictinary);        //是否符合條件 返回bool    BOOL isSelected=[blockDictionary bk_any:^BOOL(id key, id obj) {        BOOL select=[obj intValue]>20?YES:NO;        return select;    }];    NSLog(@"%d符合條件",isSelected);        //判斷是否所有的項(xiàng)都符合這個(gè)條件    BOOL allSelected=[blockDictionary bk_all:^BOOL(id key, id obj) {        BOOL select=[obj intValue]>20?YES:NO;        return select;    }];    NSLog(@"%d符合條件",allSelected);        //判斷是否所有的項(xiàng)都不符合這個(gè)條件    BOOL noneSelected=[blockDictionary bk_none:^BOOL(id key, id obj) {        BOOL select=[obj intValue]>50?YES:NO;        return select;    }];    NSLog(@"%d符合條件",noneSelected);

2:NSMutableDictionary一些常見(jiàn)的操作

    //創(chuàng)建一個(gè)nsmutabledictionary    NSMutableDictionary *mutableDictionary=[NSMutableDictionary dictionaryWithCapacity:3];    [mutableDictionary setObject:@"wujy" forKey:@"name"];    [mutableDictionary setObject:@"VEVb.com/wujy" forKey:@"webName"];    [mutableDictionary setObject:@29 forKey:@"age"];        //得到詞典中的所有key    NSEnumerator *enumeratorkey=[mutableDictionary keyEnumerator];    for (NSObject *obj in enumeratorkey) {        NSLog(@"key為：%@",obj);        NSLog(@"通過(guò)key找到value值為：%@",[mutableDictionary objectForKey:obj]);    }        //刪除其中一個(gè)key    [mutableDictionary removeObjectForKey:@"name"];    NSLog(@"刪除name的key以后值：%@",mutableDictionary);        [mutableDictionary removeAllObjects];    NSLog(@"刪除所有以后，可變?cè)~典個(gè)數(shù)為%ld",[mutableDictionary count]);        //blocks    //過(guò)濾    NSMutableDictionary *newmutableDictionary=[NSMutableDictionary dictionaryWithDictionary:@{@"IOS":@3,@"work":@13,@"age":@29}];    [newmutableDictionary bk_performSelect:^BOOL(id key, id obj) {        BOOL select=[obj intValue]>10?YES:NO;        return select;    }];    NSLog(@"過(guò)濾后的可變?cè)~典為(29,13)%@",newmutableDictionary);        //取反過(guò)濾    [newmutableDictionary bk_performReject:^BOOL(id key, id obj) {        BOOL select=[obj intValue]>20?YES:NO;        return select;    }];    NSLog(@"取反過(guò)濾的可變?cè)~典為(13)%@",newmutableDictionary);        //修改各個(gè)項(xiàng)的結(jié)果    [newmutableDictionary bk_performMap:^id(id key, id obj) {        return @([obj intValue]+1);    }];    NSLog(@"修改后的可變?cè)~典為(14)%@",newmutableDictionary);