NSArray/NSMutableArray创建,获取,遍历,排序

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1 数组基本

1.1 创建数组

NSArray 是不可变数组,一旦创建完成就不能够对数组进行,添加,删除等操作

下面这种方式相当于什么都没做

NSArray * array = [[NSArray alloc] init];NSLog(@"%@",array);1
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1.2 通过构造方法的方式创建一个NSArray

在创建一个NSArray的时候,集合的最后一个元素一定是nil

NSArray * array1 = [NSArray arrayWithObjects:@"one",@"two",@"three", nil];NSLog(@"%@",array1);1
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1.3 数组中可以存储不同类型的对象

NSNumber * number = [NSNumber numberWithInt:10];NSArray * array2 = [[NSArray alloc] initWithObjects:@"one",@"two",number, nil];NSLog(@"array2  %@",array2);1
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1.4 数组实际上存储的是对象的地址,同样也可以存储数组的地址

NSArray * a1 = [[NSArray alloc] initWithObjects:@"one",@"two",@"three", nil];NSArray * a2 = [[NSArray alloc] initWithObjects:@"1",@"2",@"3", nil];NSArray * a3 = [[NSArray alloc] initWithObjects:a1,a2, nil];NSLog(@"a3 %@",a3);1
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1.5 存储自定义的对象

最好都 description 方法

@interface Person : NSObject@property (nonatomic,strong)NSString * name;@property (nonatomic,assign)int age;- (id)initWithName:(NSString *)name andAge:(int)age;@end1
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@implementation Person- (id)initWithName:(NSString *)name andAge:(int)age{    if (self = [super init])    {        _name = name;        _age = age;    }    return self;}- (NSString *)description{    return [NSString stringWithFormat:@"age = %d name = %@",_age,_name];}@end1
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Person * p1 = [[Person alloc] initWithName:@"xiaozhe" andAge:20];Person * p2 = [[Person alloc] initWithName:@"hell" andAge:18];Person * p3 = [[Person alloc] initWithName:@"marray" andAge:38];NSArray * array3 = [[NSArray alloc] initWithObjects:p1,p2,p3, nil];NSLog(@"array3  %@",array3);1
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1.6 数组中存储基本数据类型

如果你要在数组中存储基本数据类型,请包装好了之后在去存 NSNumber

注意不要把nil值存储到 NSArray 中,会导致数据丢失

NSString * str = nil;NSArray * array4 = [[NSArray alloc] initWithObjects:@"2",str,[NSNumber numberWithInt:23], nil];NSLog(@"array4 %@",array4);1
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1.7 创建数组的快捷方式

NSArray * karray = @[@"a",@"b",@"c"];NSLog(@"karray %@",karray);1
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1.8 快速获得一个数组中的元素

NSString * kstr = karray[0];NSLog(@"kstr %@",kstr);1
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1.9 从数组中取出数据

NSArray * array = [[NSArray alloc] initWithObjects:@"one",@"two",@"three", nil];1

数组的index时从0开始的

NSString * str = [array objectAtIndex:0];NSLog(@"str %@",str);1
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1.10 获得数组的元素个数

NSUInteger arrayCount = [array count];NSLog(@"arrayCount %d",arrayCount);1
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1.11 判断数组中是否存在某个对象

Person * p1 = [[Person alloc] initWithName:@"yofer" andAge:20];Person * p2 = [[Person alloc] initWithName:@"luke" andAge:30];NSArray * array = @[p1,p2];BOOL isContain = [array containsObject:p1];if (isContain){    NSLog(@"存在");}else{    NSLog(@"不存在");}1
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2 遍历数组

2.1 使用for循环遍历数组

NSArray * array = @[@"one",@"two",@"three"];for (int i = 0; i < array.count; i++){    NSString * str = array[i];    NSLog(@"array[%d] = %@",i,str);}1
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2.2 使用增强for循环的方式遍历数组

for (NSString * str in array){    NSLog(@"str = %@",str);}1
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2.3 注意事项

如果你的数组中村粗了多种不同类型的数据,那么最好不要调用某个对象特有的方法,会导致程序崩溃

在实际的开发中,一个数组往往只负责存储一种数据类型

Person * p1 = [[Person alloc] init];NSArray * array2 = @[@"one",[NSNumber numberWithInt:10],p1];for (NSString * str in array2){//    NSLog(@"array2 str %@",str);//    NSLog(@"str %ld",str.length);}1
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2.4 枚举器

NSArray * array3 = @[@"one",@"two",@"three"];NSEnumerator * enumerateor =  [array3 objectEnumerator];NSString * value;while (value = [enumerateor nextObject]) {    NSLog(@"enum str %@",value);}1
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3 数组排序

3.1 使用 sortedArrayUsingSelector

是最简单的排序方式

数组是按照你存入元素的顺序存储的

NSArray * array = @[@"b",@"d",@"a",@"z"];NSLog(@"排序前 array %@",array);array = [array sortedArrayUsingSelector:@selector(compare:)];// NSArray * array1 = [array sortedArrayUsingSelector:@selector(compare:)];NSLog(@"排序后 array %@",array);1
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3.2 使用block方式排序

NSArray * array2 = @[@"z",@"4",@"b",@"3",@"x"];NSLog(@"array2 排序前 %@",array2);array2 = [array2 sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {    /*    NSComparisonResult retuslt = [obj1 compare:obj2];    return retuslt;     */    //obj1 compare obj2 就是正序排序    //  return [obj1 compare:obj2];    //obj2 compare obj1 就是倒序排序    return [obj2 compare:obj1];}];NSLog(@"array2 排序后 %@",array2);1
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先给一个 Person 类

@interface Person : NSObject@property (nonatomic,assign) int age;@property (nonatomic,strong) NSString * name;@property (nonatomic,strong) NSString * year;- (id)initWithName:(NSString *)name  andAge:(int)age andYear:(NSString *)year;//+ (id)personWithName:(NSString *)name  andAge:(int)age andYear:(NSString *)year;@end1
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@implementation Person- (id)initWithName:(NSString *)name  andAge:(int)age andYear:(NSString *)year{    if (self = [super init])    {        _name = name;        _age = age;        _year = year;    }    return self;}- (NSString *)description{    return [NSString stringWithFormat:@"name %@ age %d year %@",_name,_age,_year];}@end1
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3.3 定制化数组对象排序

Person * p1 = [[Person alloc] initWithName:@"xiaozhe" andAge:20 andYear:@"1990"];Person * p2 = [[Person alloc] initWithName:@"alex" andAge:18 andYear:@"2990"];Person * p3 = [[Person alloc] initWithName:@"merry" andAge:25 andYear:@"1890"];NSArray * array3 = @[p1,p2,p3];NSLog(@"array3 排序前 %@",array3);1
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如果你向给你自己定义的对象排序,必须根据某一个属性来排序,

sortDescriptorWithKey 参数要的就是你对象中,要依据哪个属性来排序,你就把哪个属性的名字当成key传入

ascending YES表示正序 NO表示倒序

NSSortDescriptor * d1 = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:NO];NSSortDescriptor * d2 = [NSSortDescriptor sortDescriptorWithKey:@"year" ascending:NO];1
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如果你要使用多个属性进行排序,默认在前面的NSSortDescriptor优先级比较高

NSArray * descripts = @[d2,d1];array3 = [array3 sortedArrayUsingDescriptors:descripts];NSLog(@"array 3 排序后  %@",array3);1
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结果：

2016-08-14 14:13:57.238 05-数组排序[2105:516991] array3 排序前 (    "name xiaozhe age 20 year 1990",    "name alex age 18 year 2990",    "name merry age 25 year 1890")2016-08-14 14:13:57.238 05-数组排序[2105:516991] array 3 排序后  (    "name alex age 18 year 2990",    "name xiaozhe age 20 year 1990",    "name merry age 25 year 1890")1
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再次测试：

NSArray * array4 = @[p1,p2,p3];NSLog(@"array4 排序前 %@",array4);array4 = [array4 sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {    Person * p1 = obj1;    Person * p2 = obj2;    //year    return [p1.year compare:p2.year];}];NSLog(@"array4 排序后 %@",array4);1
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结果：

2016-08-14 14:13:57.238 05-数组排序[2105:516991] array4 排序前 (    "name xiaozhe age 20 year 1990",    "name alex age 18 year 2990",    "name merry age 25 year 1890")2016-08-14 14:13:57.238 05-数组排序[2105:516991] array4 排序后 (    "name merry age 25 year 1890",    "name xiaozhe age 20 year 1990",    "name alex age 18 year 2990")1
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4 可变数组: NSMutableArray

NSMutableArray 继承至 NSArray

4.1 创建可变数组

NSMutableArray * array = [[NSMutableArray alloc] initWithCapacity:0];1

使用addObject 动态给数组中增加元素

[array addObject:@"one"];[array addObject:@"two"];[array addObject:@"three"];[array addObject:@"one"];NSString * str1 = @"one";NSString * str2 = @"two";NSString * str3 = @"three";1
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数组中可以存储,同一个对象多次

[array addObject:str1];[array addObject:str2];[array addObject:str3];[array addObject:str1];1
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4.2 指定对象插入的位置

[array insertObject:str1 atIndex:2];1

4.3 删除会通过对象,删除数组中所有的同一个地址的对象

[array removeObject:str1];1

4.4 通过索引的方式删除对象,超出了数组的count值,那么就会导致异常 index beyond bounds

[array removeObjectAtIndex:0];[array addObject:str2];[array addObject:str3];[array addObject:str1];1
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4.5 删除数组中所有的元素

[array removeAllObjects];NSLog(@"array %@",array);[array addObject:str2];[array addObject:str3];[array addObject:str1];1
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5 可变数组 NSMutableArray 遍历

5.1 for换遍历

for (int i = 0; i < array.count; i++){    NSString * str = [array objectAtIndex:i];    //在遍历数组的时候,千万不要给数组中,增加,或者删除元素    // [array removeObject:str1];    NSLog(@"str %@",str);}1
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5.2 增强for循环

for (NSString * str in array){//    [array removeObject:str1];    //如果你在增强for循环中,删除元素,会直接导致异常出现    NSLog(@"str %@",str);}1
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5.3 枚举器

NSEnumerator * enumerator = [array objectEnumerator];NSString * value;while (value = [enumerator nextObject]) {    //如果你在枚举器中,删除元素,会直接导致异常出现//    [array removeObject:str1];    NSLog(@"str %@",value);}1
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5.4 要通过遍历的方式确定删除哪个元素怎么办

NSMutableArray * array2 = [[NSMutableArray alloc] init];[array2 addObject:@"1"];[array2 addObject:@"2"];[array2 addObject:@"3"];[array2 addObject:@"4"];[array2 addObject:@"5"];NSMutableArray * tmp = [[NSMutableArray alloc] init];for (NSString * str in array2){    if ([str isEqualToString:@"3"])    {        [tmp addObject:str];    }}NSLog(@"array2 %@",array2);NSLog(@"tmp %@",tmp);1
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结果：

2016-08-14 14:35:20.437 06-可变数组[2252:538261] array2 (    1,    2,    3,    4,    5)2016-08-14 14:35:20.437 06-可变数组[2252:538261] tmp (    3)1
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遍历临时数组

for (int i = 0; i < tmp.count; i++){    NSString * str = [tmp objectAtIndex:i];    //从原数组中删除,临时数组中存储的对象    [array2 removeObject:str];}NSLog(@"array2 %@",array2);1
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新博客文章地址：NSArray/NSMutableArray创建,获取,遍历,排序

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