【轉載】oc語言基礎知識全面 看完oc基礎教程後再溫習一遍

"];
1.以某些字元開頭 hasPrefix:)#> 後面填寫的是字串物件 @“”;返回值是一個bool型別 0或者1
BOOL isPrefix = [str4 hasPrefix:@"http"];
2,.以某些字元結束 hasSuffix:)#> 後面填寫的是字串物件 @“”;返回值是一個bool型別 0或者1
BOOL isSuffix = [str4 hasSuffix:@"com”];
3.查詢指定字串的範圍 rangeOfString:)#> - (NSRange)rangeOfString:(NSString )aString NSRange結構體重新命名得到的 返回值為:range.location 和range.length 只查詢有沒有 而不管有幾個 如果有返回開始下表和長度
NSRange range/(NSString NSStringFromRange)和前面的等價/ = [str4 rangeOfString:@"http"];
if (range.length == 0) {
NSLog(@"沒有相關的字串");
}else{
//將NSRange 結構體型別變數直接轉換成字串物件輸出
A structure used to describe a portion of a series—such as characters in a string or objects in an NSArray object.
/ typedef struct _NSRange {
NSUInteger location;
NSUInteger length;
} NSRange;
/
NSLog(@"%@",NSStringFromRange(range)); {0,4}返回值
//NSLog(@"locatio = %lu,length = %lu",range.location,range.length);等價於上面的方法

NSString * NSStringFromRange (
NSRange range);
}

1. 字串擷取 從給定下表到結束 substringFromIndex substringToIndex substringWithRange 由於操作的是不可變的字串 這裡操作的是副本
   NSString str5 = [NSString stringWithFormat:@"lanou is a big company"]; //便利構造器的方法 快速產生字串物件
   1.獲取給定下標之後的字串,包含指定下標對應的字元 空格也要算在內 from包含
   //例如要獲取company
   NSString subString1 = [str5 substringFromIndex:15];
   NSLog(@"subString = %@",subString1);
   2.獲取給定下標之前的字串,不包含指定下標對應的字元 空格也要算在內 to不包含
   // 如:lanou
   NSString *subString2 = [str5 substringToIndex:5];
   NSLog(@"subString = %@",subString2);

3.獲取制定一個範圍的字串 substringWithRange Returns a string object containing the characters of the receiver that lie within a given range.

• (NSString )substringWithRange:(NSRange)aRange
  //例如獲取:lanou 利用NSMakeRange(0, 5)
  NSString subString3 = [str5 substringWithRange:NSMakeRange(0, 5)];
  NSLog(@"subString3 = %@",subString3);
  4.字串拼接 stringByAppendingFormat Returns a string made by appending to the receiver a string constructed from a given format string and the following arguments.
• (NSString )stringByAppendingFormat:(NSString )format, ...
  stringByAppendingString Returns a new string made by appending a given string to the receiver.
• (NSString )stringByAppendingString:(NSString )aString
  NSString str6 = [NSString stringWithFormat:@"lanou"];
  //lanou 後拼接 henan
  NSString newStr6 = [str6 stringByAppendingString:@"henan"];//不可以出現格式串
  NSLog(@"newStr6 = %@",newStr6);
  //lanou 後拼接 henan9ban
  NSString newStr7 = [str6 stringByAppendingFormat:@"henan%dban",9];//可以出現格式串
  NSLog(@"newStr7 = %@",newStr7);
  NSString newStr8 = [str6 stringByAppendingFormat:@"%@",newStr7];//特別注意可以拼接物件
  NSLog(@"newStr8 = %@",newStr8);

5.替換字串 stringByReplacingOccurrencesOfString: withString: Returns a new string in which all occurrences of a target string in the receiver are replaced by another given string.

• (NSString )stringByReplacingOccurrencesOfString:(NSString )target withString:(NSString )replacement
  NSString str8 = [NSString stringWithFormat:@"lan ouououououououou isabigcompany"];
  //(1)將ou替換成nb
  NSString newStr9 = [str8 stringByReplacingOccurrencesOfString:@"ou"withString:@"牛逼"]; //換掉誰誰在前 換上誰 誰在前
  NSLog(@"newStr8 = %@",newStr9);
  //2.只將第一個ou換成牛逼 如果替換兩個 就寫兩次 牛逼
  NSString newStr10 = [str8 stringByReplacingCharactersInRange:NSMakeRange(4, 2) withString:@"牛逼"];
  NSLog(@"%@",newStr10);

6.字串比較 返回值為 列舉型別
Returns the result of invoking compare:options:range: with no options and the receiver’s full extent as the range.

• (NSComparisonResult)compare:(NSString *)aString
  NSComparisonResult 返回值型別 列舉型別
  
  NSComparisonResult result = [@"111" compare:@"222"];//前一個比後一個小 升序返回 -1
  NSLog(@"%ld",result);

7.將數字轉為字串物件
NSString *str12 = [NSString stringWithFormat:@"%f",5.2];//將5.2轉換為字串物件
1.字串大小寫轉換

8.字串的大小寫轉換函式

1.將@"lan ghasgda HGASIDHH JHFWIEFH J OU"全部轉換成大寫 uppercaseString Returns a uppercased(大寫字母印刷 ) representation of the receiver.

• (NSString *)uppercaseString 無引數 有返回值 訊息傳送機制

  NSString *upperString = [@"lan ghasgda HGASIDHH JHFWIEFH J  OU" uppercaseString];
  NSLog(@"upperString = %@",upperString);

2.將@"lan SJA Hjknjkjnkdj sdjkjsd OU"全部轉換成小寫 lowercaseString Returns lowercased representation of the receiver.

• (NSString )lowercaseString 無引數 有返回值 訊息傳送機制
  NSString lowerString = [@"lan SJA Hjknjkjnkdj sdjkjsd OU" lowercaseString];
  NSLog(@"lowerString = %@",lowerString);
  3.將@"lan bdfh bsdjksbajf jksdbfjkwdbfjk OU"首轉換成大寫 capitalizedString Returns a capitalized(首字母大寫的) representation of the receiver.
• (NSString )capitalizedString 無引數 有返回值 訊息傳送機制
  NSString capitilizedString = [@"lan bdfh bsdjksbajf jksdbfjkwdbfjk OU" capitalizedString];
  NSLog(@"capitilizedString = %@",capitilizedString);
  常用的可變字串處理例項方法

NSMutableString 這裡需要注意的是該方法的處理方式是在原字串上直接進行修改
1.– appendFormat:
Adds a constructed string to the receiver.
新增一個字串構造的接收器

• (void)appendFormat:(NSString )format …
  NSMutableString str = [NSMutableString stringWithFormat:@"lanouhenan"];
  //1.在原字串的基礎上拼接Frank appendFormat 對於字串的修改都是在字串基礎上修改,所以修改完的字串內容發生變化 所以不需要返回值
  [str appendFormat:@"Frank"];
  NSLog(@"%@",str);// lanouhenanFrank

2.– appendString:
Adds to the end of the receiver the characters of a given string.
增加了接收器的端部在給定的字串的字元

• (void)appendString:(NSString *)aString

  NSMutableString *str = [NSMutableString stringWithFormat:@"lanouhenan”];
  //2.在原字串的基礎上拼接Frank
  [str appendString:@"Frank”];
  NSLog(@"%@",str);// lanouhenanFrankFrank
  •

•
• 3.– deleteCharactersInRange:
•
Removes from the receiver the characters in a given range.
從接收機中刪除給定範圍內的字元

• (void)deleteCharactersInRange:(NSRange)aRange

NSMutableString *str = [NSMutableString stringWithFormat:@"lanouhenan”];
//3.刪除字串 在原字串基礎上刪除
//如 刪除 henan
[str deleteCharactersInRange:NSMakeRange(5, 5)];
NSLog(@"%@",str);//lanouhenanFrankFrank
•
•
• 4.– insertString:atIndex:
•
Inserts into the receiver the characters of a given string at a given location.
插入到接收器給定的字串中的字元在給定的位置。

• (void)insertString:(NSString )aString atIndex:(NSUInteger)anIndex
  NSMutableString str = [NSMutableString stringWithFormat:@"lanouhenan”];
  //4.插入字串 在原字串基礎上插入
  [str insertString:@"henan" atIndex:5];
  NSLog(@"%@",str);//lanouhenanFrankFrank

• 5.– replaceCharactersInRange:withString:
•
Replaces the characters from aRange with those in aString.
取代了aRange人物與那些在ASTRING。

• (void)replaceCharactersInRange:(NSRange)aRange withString:(NSString )aString
  NSMutableString str = [NSMutableString stringWithFormat:@"lanouhenan”];
  //5.替換字串 在元字串基礎上將Frank替換成Duck
  [str replaceCharactersInRange:NSMakeRange(10, 5) withString:@"Duck"];
  NSLog(@"%@",str);//lanouhenanDuckFrank

• 6.– replaceOccurrencesOfString:withString:options:range:
•
Replaces all occurrences of a given string in a given range with another given string, returning the number of replacements.
替換在給定的範圍內與其他給定的字串給定的字串的所有匹配，返回替換的數量。

• (NSUInteger)replaceOccurrencesOfString:(NSString )target withString:(NSString )replacement options:(NSStringCompareOptions)opts range:(NSRange)searchRange
  NSMutableString str1 = [NSMutableString stringWithFormat:@"lanouhenanjdsfhdfhjdfsdjfj”]; //可變的字串處理函式
  NSString str13 = [str1 stringByReplacingCharactersInRange:NSMakeRange(10, 5) withString:@"Duck”];//不可變的字串處理函式
  NSLog(@"%@",str1);//lanouhenanjdsfhdfhjdfsdjfj
  NSLog(@"%@",str13);//lanouhenanDuckdfhjdfsdjfj
  //這裡可以結合函式的傳值呼叫和傳址呼叫,需要明白的NSString在處理字串物件時是將字串複製副本,針對副本進行操作 所以上面的返回值裡有兩中不同的結果.

• 7.– setString:
•

Replaces the characters of the receiver with those in a given string.
替換與一個給定的字串中的接收器的特徵。

• (void)setString:(NSString )aString
  NSMutableString str = [NSMutableString stringWithFormat:@"lanouhenan”];
  注:本文中的所有程式碼需要前後結合來看.
  陣列的價值:(1)存數多個元素(2)儲存元素只能是物件,物件可以是不同型別(3)陣列是一個有序的集合(4)陣列中的元素可以重複,而且重複的元素可以成為陣列元素
  NSArray 不可變陣列物件
  Creating an Array 利用便利構造器方法

  1. arrayWithObjects:
     Creates and returns an array containing the objects in the argument list.
     建立並返回包含在引數列表中的物件的陣列。
• (instancetype)arrayWithObjects:(id)firstObj,,…

1. initWithObjects:
   Initializes a newly allocated set with members taken from the specified list of objects.
   初始化一個新分配的一套從物件的指定名單中的成員。

• (instancetype)initWithObjects:(id)firstObj, …
  建立陣列物件
  //1.使用便利構造器
  //1.arrayWithObjects 元素與元素之間用逗號間隔 輸出格式 (aa,bb,cc)
  //2.以nil結束 nil後面的元素都不會放入陣列中
  NSArray arr1 = [NSArray arrayWithObjects:@"aa",@"bb",@"5",nil,@"cc", nil];
  NSLog(@"arr1 = %@",arr1);//arr1 = (aa,bb,5)
  //2.使用初始化方法
  NSArray arr2 = [[NSArray alloc] initWithObjects:@"aa",@"bb",@"5",nil,@"cc",nil];
  NSLog(@"arr2 = %@",arr2);//arr2 = (aa,bb,5)

1. count:
   Returns the number of objects currently in the array.
   返回當前陣列的物件的數量。

• (NSUInteger)count
  獲取元素個數
  NSUInteger count = [arr2 count];
  NSLog(@"count = %lu",count); //count = 3;

1. objectAtIndex:透過下標取元素
   Returns the object at the specified index of the set.
   返回集合的指定索引處的物件。

• (id)objectAtIndex:(NSUInteger)index

1. firstObject:
   Returns the first object in the array.
   返回的陣列中的第一個物件。

• (id)firstObject

1. lastObject:
   Returns the last object in the ordered set.

返回的有序集合的最後一個物件。

• (id)lastObject
  根據索引值獲取物件
  //(1)獲取制定下標的元素
  NSString str = [arr2 objectAtIndex:1];
  NSLog(@"str = %@",str);//str = bb;
  //(2)獲取陣列中第一個元素 //The first object in the array. If the array is empty, returns nil. first和last方法比objectAtIndex更加安全,當陣列元素為空時會返回null,而objectAtIndex會造成程式的crash.即陣列下標越界.
  NSString str1 = [arr2 firstObject];
  NSLog(@"str1 = %@",str1);//str1 = aa
  NSString str2 = [arr2 objectAtIndex:0];
  NSLog(@"str2 = %@",str2);//str2 = aa
  //(3)獲取陣列中最後個元素
  NSString str3 = [arr2 lastObject];
  NSLog(@"str3 = %@",str3);//str3 = 5

7.indexOfObject:透過物件返回下標
Returns the index of the specified object.
返回指定物件的索引。

• (NSUInteger)indexOfObject:(id)object
  獲取陣列物件在陣列中的索引值; Returns the lowest index whose corresponding array value is equal to a given object.陣列中的元素可以重複,返回的為第一個.
  NSUInteger index = [arr2 indexOfObject:@"5"];
  NSLog(@"index = %lu",index);//index = 2

1. containsObject:判斷某一個物件是否存在於陣列中
   Returns a Boolean value that indicates whether a given object is present in the set.
   返回一個布林值，表示給定的物件是否存在於集合中。

• (BOOL)containsObject:(id)anObject
  判斷是否包含某個物件. Returns a Boolean value that indicates whether a given object is present in the set.//返回值為bool型別.
  BOOL isExist = [arr2 containsObject:@"aa"];
  NSLog(@"isExist = %d",isExist);//isExist = 1

1. sortedArrayUsingSelector:
   Returns an array that lists the receiving array’s elements in ascending order, as determined by the comparison method specified by a given selector.
   • (NSArray )sortedArrayUsingSelector:(SEL)comparator
     陣列排序
     NSArray sortArr = [arr2 sortedArrayUsingSelector:@selector(compare:)];//這裡傳入的是比較方法
     NSLog(@"sortArr = %@", sortArr);

10.forin

快速遍歷(快速列舉)
for (int i = 0; i NSString str4 = [arr2 objectAtIndex:i];
NSLog(@"%@",str4);
}
/
for (type object(陣列元素型別 物件名字) in collection(集合即:要取元素的陣列)) {
statements 輸出語句
} forin 快速遍歷,用於將集合中的元素遍歷出來.
/

    for (NSString *str4 in arr2) {
        NSLog(@"%@",str4);
    }

NSMutableArray 可變的陣列物件處理函式
首先建立陣列物件,然後針對陣列物件進行操作
//建立陣列物件
NSMutableArray *arr1 = [[NSMutableArray alloc] initWithObjects:@"aa",@"bb",@"cc",@"vbvh"@"jd",@"jhsfcu",@"dfdh", nil];

1.addObject:
Inserts a given object at the end of the array.

• (void)addObject:(id)anObject
  //1.新增元素
  [arr1 addObject:@"Frank"];
  NSLog(@"arr1 = %@",arr1);

2.insertObject:atIndex:
Inserts a given object into the array's contents at a given index.

• (void)insertObject:(id)anObject atIndex:(NSUInteger)index
  //2.插入元素 將Duck新增到aa的後面
  [arr1 insertObject:@"Duck" atIndex:1];
  NSLog(@"arr1 = %@",arr1);

1. removeAllObjects
   Empties the array of all its elements.
   • (void)removeAllObjects
     4.removeObjectAtIndex:
     Removes the object at index .
   • (void)removeObjectAtIndex:(NSUInteger)index
     //3.刪除元素
     //1.將Duck刪除
     [arr1 removeObjectAtIndex:3];
     NSLog(@"arr1 = %@",arr1);
     //2.刪除所有元素
     // [arr1 removeAllObjects];
     // NSLog(@"arr1 = %@",arr1);

5.replaceObjectsInRange:withObjectsFromArray:range:
Replaces the objects in the receiving array specified by one given range with the objects in another array specified by another range.

• (void)replaceObjectsInRange:(NSRange)aRange withObjectsFromArray:(NSArray *)otherArray range:(NSRange)otherRange
  //4.替換元素
  //將Frank替換成"shuaige"
  [arr1 replaceObjectAtIndex:6 withObject:@"shuaige"];
  NSLog(@"arr1 = %@",arr1);

6.exchangeObjectAtIndex:withObjectAtIndex:
Exchanges the objects in the array at given indices.

• (void)exchangeObjectAtIndex:(NSUInteger)idx1(下標) withObjectAtIndex:(NSUInteger)idx2(下標)
  //5.交換指定的位置
  [arr1 exchangeObjectAtIndex:0 withObjectAtIndex:2];
  NSLog(@"arr1 = %@",arr1);

7.sortUsingSelector:
Sorts the array’s elements in ascending order, as determined by the comparison method specified by a given selector.

• (void)sortUsingSelector:(SEL)comparator
  //6.對原陣列進行排序 按照ASCII碼進行排序
  [arr1 sortUsingSelector:@selector(compare:)];
  NSLog(@"arr1 = %@",arr1);

//7.快速遍歷
for (NSString *str5 in arr1) {
NSLog(@"%@",str5);
}
//如果陣列中元素型別不同,輸出時使用統一的泛型 id 可代表所有的物件型別.
for (id str5 in arr1) {
NSLog(@"%@",str5);
}
數值物件 NSNumber
1.numberWithChar:
Creates and returns an NSNumber object containing a given value, treating it as a signed char.

• (NSNumber *)numberWithChar:(char)value

2.charValue
Returns the receiver’s value as a char.

• (char)charValue
  //將基本資料型別轉化成數值物件
  //1.定義接本資料型別變數
  char a = 'f';
  int b = 20;
  short c = 100;
  long d = 1000;
  float e = 12.345;
  double f = 10.2222;
  BOOL isTrue = YES;
  //2.將基本資料型別轉換成資料物件 全部轉換成對應的數值 儲存在堆區
  //相當於中介
  NSNumber a1 = [NSNumber numberWithChar:a ];
  NSNumber a2 = [NSNumber numberWithInt:b ];
  NSNumber a3 = [NSNumber numberWithShort:c ];
  NSNumber a4 = [NSNumber numberWithLong:d ];
  NSNumber a5 = [NSNumber numberWithFloat:e ];
  NSNumber a6 = [NSNumber numberWithDouble:f ];
  NSNumber a7 = [NSNumber numberWithBool:isTrue];
  NSArray arr = [NSArray arrayWithObjects:a1,a2,a3,a4,a5,a6,a7 ,nil];
  NSLog(@"%@",arr);//列印陣列
  //列印數值物件
  NSLog(@"%@",a1);
  NSLog(@"%@",a2);
  NSLog(@"%@",a3);
  NSLog(@"%@",a4);
  NSLog(@"%@",a5);
  NSLog(@"%@",a6);
  NSLog(@"%@",a7);
  //3.將NSNumber轉換成基本資料
  char b1 = [a1 charValue];
  NSLog(@"%c",b1);
  int b2 = [a2 intValue];
  NSLog(@"%d",b2);
  //4.NSNumber型別資料的比較
  NSLog(@"%ld",[a1 compare:a2]);//注意物件比較對向

上述具體結果如下:
2014-08-07 18:59:26.555 LessonNnumber[8367:303] (
102,
20,
100,
1000,
"12.345",
"10.2222",
1
)
2014-08-07 18:59:26.556 LessonNnumber[8367:303] 102
2014-08-07 18:59:26.557 LessonNnumber[8367:303] 20
2014-08-07 18:59:26.557 LessonNnumber[8367:303] 100
2014-08-07 18:59:26.558 LessonNnumber[8367:303] 1000
2014-08-07 18:59:26.558 LessonNnumber[8367:303] 12.345
2014-08-07 18:59:26.558 LessonNnumber[8367:303] 10.2222
2014-08-07 18:59:26.559 LessonNnumber[8367:303] 1
2014-08-07 18:59:26.559 LessonNnumber[8367:303] f
2014-08-07 18:59:26.559 LessonNnumber[8367:303] 20
2014-08-07 18:59:26.560 LessonNnumber[8367:303] 1
http://developer.51cto.com/art/201407/444542_1.htm

24.字典
1.字典 作用:(1)儲存多個資料 (2)用來儲存的資料具有一一對應關係(使用key和value來標識) (3)對於字典中的一對鍵值對叫做字典中的元素,也就一個條目,只要是物件就可以,不做具體的資料類型別的限制4.字典是無序的(字典中關鍵字key是唯一標示的 一個key只能對應一個value,一個value可以對應多個key)
2.建立不可變字典物件 {元素 ;號間隔}不可變的字典一旦建立就不能修改為只讀模式.
1.便利構造器的方法 這裡要注意:鍵值對是成對出現的 到nil結束
dictionaryWithObjectsAndKeys +號方法 用於建立一個物件 快速建立 Creates and returns a dictionary containing entries constructed from the specified set of values and keys.

• (instancetype)dictionaryWithObjectsAndKeys:(id)firstObject, , ...
  NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:@"zhgds",@"name",@20,@"hight",@12,@"age",nil];

  NSLog(@"%@",dic);

2.初始化物件的方法 -號方法 開闢空間 初始化物件 initWithObjectsAndKeys Initializes a newly allocated dictionary with entries constructed from the specified set of values and keys.

• (instancetype)initWithObjectsAndKeys:(id)firstObject, , ...

  NSDictionary *dic1 = [[NSDictionary alloc] initWithObjectsAndKeys:@"zhgds",@"name",@20,@"hight",@12,@"age",nil];
  NSLog(@"%@",dic1);

3.求字典中元素的個數 count Returns the number of entries in the dictionary.

• (NSUInteger)count
  NSLog(@"%lu",[dic count]);
  4.獲取字典中所有key Returns a new array containing the dictionary’s keys.
• (NSArray *)allKeys 注意返回值為一個陣列

NSArray *keys = [dic allKeys];

    NSLog(@"%@",keys); 

5.objectForKey 根據key獲取對應的value 根據物件取值 型別一定要匹配
NSString name = [dic objectForKey:@"name"];
NSLog(@"%@",name);
NSNumber age = [dic objectForKey:@"age"];
NSLog(@"%@",age);
NSNumber *hight = [dic objectForKey:@"hight"];
NSLog(@"%@",hight);

1. 快速遍歷 對於陣列來說遍歷到的是陣列中的元素 對於字典來時遍歷到的是key 一個key對應一個value 但value可以對應多個key
   for (NSString *k in dic) {
   //檢索到key之後獲取對應的value.
   NSLog(@"%@",[dic objectForKey:k]);
   }

7.建立可變字典物件 NSMutableDictionary
1.建立物件的兩種方式 便利構造器和初始化
NSMutableDictionary dic = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"xiaoguang",@"guanggun1",@"xiaoshuai",@"guanggun2",@"xiaomeng",@"guanggun3", nil];
NSLog(@"%@",dic);
NSMutableDictionary dic1 = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@"xiaoguang",@"guanggun1",@"xiaoshuai",@"guanggun2",@"xiaomeng",@"guanggun3", nil];
NSLog(@"%@",dic1);

2.求字典元素個數 同樣是 count 返回值是一個整形的數
NSLog(@"%lu",[dic count]);

3.刪除元素 removeObjectForKey removeAllObjects
[dic removeObjectForKey:@"guanggun1"];
NSLog(@"%@",dic);
[dic removeAllObjects];
NSLog(@"%@",dic);
4.新增元素 setObject需要特別注意 這裡用的是set方法
[dic setObject:@"chengjie" forKey:@"guanggun1"];
NSLog(@"%@",dic);

5.修改key對應的value
[dic setObject:@"xiaocun" forKey:@"guanggun1"];
NSLog(@"%@",dic);
setObject:forKey:工作原理:根據指定key查詢字典中是否存在相同的,若果存在則修改對應的value ,若果不存在,在字典中新增一個元素key-value鍵值對.

6.快速遍歷 對於陣列來說遍歷到的是陣列中的元素 對於字典來時遍歷到的是key 一個key對應一個value 但value可以對應多個key
for (NSString *k in dic) {
//檢索到key之後獲取對應的value.
NSLog(@"%@",[dic objectForKey:k]);
}

25.集 集合類 NSSet 不可變集合
1.建立集合物件 兩種方法 便利構造器 初始化方法 輸出規範 {(元素,號間隔)} setWithObjects initWithObjects
NSSet set1 = [NSSet setWithObjects:@"1",@"2",@"3",@"4",@"5",@"6", nil];
NSLog(@"%@",set1);
NSSet set = [[NSSet alloc] initWithObjects:@"1dghdaj",@"2",@"3hsdflds",@"4",@"5",@"6", nil];
NSLog(@"%@",set);

2.獲取元素個數 count
NSLog(@"%lu",[set count]);

3.獲取集合的某個元素
NSString *str = [set anyObject];
NSLog(@"%@",str);

    NSString *str1 = [set anyObject];
    NSLog(@"%@",str1);

    NSString *str2 = [set anyObject];
    NSLog(@"%@",str2);

    NSString *str3 = [set anyObject];
    NSLog(@"%@",str3);

獲取原則 :怎麼方便怎麼獲取 可能是隨機 但以上三種輸出結果都一樣 也不是隨機 具體理解請參考API文件
4.判斷集合中是否包含某個元素 containsObject
BOOL isExist = [set containsObject:@"2"];
NSLog(@"isExist = %d",isExist);

5.可變集合 建立物件兩種方式 便利構造器 初始化
1.便利構造器 setWithObjects
NSMutableSet *set1 = [NSMutableSet setWithObjects:@"1",@"2",@"3",@"4",@"5",@"6", nil];
NSLog(@"%@",set1);

2.初始化方法
NSMutableSet *set1 = [[NSMutableSet alloc] initWithObjects:@"1",@"2",@"3",@"4",@"5",@"6", nil];
NSLog(@"%@",set1);

2.新增元素到集合中 利用 addObject:新增物件
[set1 addObject:@"6"];
NSLog(@"%@",set1);

3.移除集合中的物件的方法 removeObject
[set1 removeObject:@"5"];
NSLog(@"%@",set1);

26.排序高階
針對物件的不同屬性的例項方法進行排序
1.main.m檔案裡

import import "Person.h"

int main(int argc, const char argv[])
{
@autoreleasepool {
//建立四個物件
Person xiaoli = [[Person alloc]initWithName:@"xiaoli" age:18 height:172];
Person zhangsan = [[Person alloc] initWithName:@"zhangsan" age:20 height:175];
Person lisi = [[Person alloc] initWithName:@"lisi" age:21 height:168];
Person wangwu = [[Person alloc] initWithName:@"wangwu" age:24 height:182];
//將物件存入陣列中.
NSArray arr = [NSArray arrayWithObjects:xiaoli,zhangsan,lisi,wangwu, nil];
//sortedArrayUsingSelector適用於升序排序以及系統自定義的類進行排序
//對陣列物件按姓名升序排列
NSArray sortArrName =[arr sortedArrayUsingSelector:@selector(compareByName:)];
NSLog(@"%@",sortArrName);
//對陣列物件按年齡升序排列
NSArray sortarrage = [arr sortedArrayUsingSelector:@selector(compareByAge:)];
NSLog(@"%@",sortarrage);
//對陣列物件按身高升序排列
NSArray sortarrheight = [arr sortedArrayUsingSelector:@selector(compareByHeight:)];
NSLog(@"%@",sortarrheight);
//對陣列物件按姓名降序排列
NSArray sortarrnameDesecending =[arr sortedArrayUsingSelector:@selector(compareByAge:)];
NSLog(@"%@",sortarrnameDesecending);
//對字串陣列進行排序
//block的排序方式適用於陣列中的物件是系統型別時 並且是降序排列時
NSArray arr1 = [[NSArray alloc] initWithObjects:@"aa",@"bb",@"cc",@"dd",@"ee",@"ff", nil];
//1.對陣列進行升序排序
NSArray sortArrAscending = [arr1 sortedArrayUsingSelector:@selector(compare:)];
NSLog(@"%@",sortArrAscending);
//1.對陣列進行降序排序
NSString sortArrDescending =[arr1 sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
//對block匿名函式實現,比較方法
//將id 轉為NSString型別
NSString str1 = (NSString )obj1;
NSString str2 = (NSString *)obj2;
//2.字串比較
return -[str1 compare:str2];
}];
NSLog(@"%@",sortArrDescending);
}
return 0;
}

Person.h檔案裡

import

@interface Person : NSObject
{
NSString *_name;// 姓名
NSInteger _age;//年齡
CGFloat _height;//身
}
//設定名字

• (void)setName:(NSString *)name;
  //訪問名字
• (NSString *)getName;
  //設定年齡
• (void)setAge:(NSInteger)age;
  //訪問年齡
• (NSInteger)getAge;
• (void)setHeight:(CGFloat)height;
• (CGFloat)getHeight;
  //初始化方法
• (id)description;
  //定義初始化方法
• (id)initWithName:(NSString *)name age:(NSInteger)age height:(CGFloat)height;
  //新增比較方法 compare NSComparisonResult列舉結果
• (NSComparisonResult)compareByAge:(Person *)anotherPerson;
• (NSComparisonResult)compareByHeight:(Person *)anotherPerson;
• (NSComparisonResult)compareByName:(Person *)anotherPerson;
• (NSComparisonResult)compareByNameDesecending:(Person *)anotherPerson;
  @end

Person .m 檔案裡

import "Person.h"

@implementation Person

pragma mark - setter and getter

//設定名字

• (void)setName:(NSString *)name{
  _name = name;
  }
  //訪問名字
• (NSString *)getName{
  return _name;
  }
  //設定年齡
• (void)setAge:(NSInteger)age{
  _age = age;
  }
  //訪問年齡
• (NSInteger)getAge{
  return _age;
  }
• (void)setHeight:(CGFloat)height{
  _height = height;
  }
• (CGFloat)getHeight{
  return _height;
  }
  pragma mark - override method
• (id)description{
  return [NSString stringWithFormat:@"name:%@,age:%ld,height:%g",_name,_age,_height];
  }
  pragma mark - init method
• (id)initWithName:(NSString *)name age:(NSInteger)age height:(CGFloat)height{
  self = [super init];
  if (self) {
  _name = name;
  _age = age;
  _height =height;
  }
  return self;
  }
  pragma mark - compare method

  //新增比較方法 compare NSComparisonResult列舉結果
  //比較年齡

• (NSComparisonResult)compareByAge:(Person *)anotherPerson{
  if ([self getAge] > [anotherPerson getAge]) {
  return NSOrderedDescending;//對應的是 1
  } else if ([self getAge] == [anotherPerson getAge]){
  return NSOrderedSame;//對應的是 0
  } else {
  return NSOrderedAscending;//對應的是 -1
  }
  }
  //比較身高
• (NSComparisonResult)compareByHeight:(Person *)anotherPerson{
  if ([self getHeight] > [anotherPerson getHeight]) {
  return NSOrderedDescending;//對應的是 1
  } else if ([self getHeight] == [anotherPerson getHeight]){
  return NSOrderedSame;//對應的是 0
  } else {
  return NSOrderedAscending;//對應的是 -1
  }
  }
• (NSComparisonResult)compareByName:(Person *)anotherPerson{
  return [[self getName] compare:[anotherPerson getName]];
  }
• (NSComparisonResult)compareByNameDesecending:(Person *)anotherPerson{
  return - [[self getName] compare:[anotherPerson getName]];
  }
  @end