NSArray

• NSArray基本用法

void arrayTest1()
{
    //数组初始化最后必须以nil结尾，表示数组元素结束
    NSArray *array1 = [[NSArray alloc]initWithObjects:@"item0",@"item1",@"item2",@"item3",@"item4",nil];
    NSLog(@"%@",array1);
    /*(
     item1,
     item2,
     item3,
     item4
     )*/
    
    //获取数组元素个数
    NSLog(@"array count : %ld",array1.count);
    /*array count : 4*/
   
    //获取特定所以元素
    NSLog(@"array[1] = %@",array1[1]);
    /* array[1] = item1 */
    NSLog(@"array[1] = %@",[array1 objectAtIndex:(NSInteger)1]);
    /* array[1] = item1 */
    NSLog(@"firstObject = %@",array1.firstObject);  //获取第一个元素
    /* firstObject = item1 */
    NSLog(@"lastObject = %@",array1.lastObject);    //获取最后一个元素
    /* lastObject = item4 */
    
    //拼接数组
    NSLog(@"%@",[array1 componentsJoinedByString:@","]);
    /* item0,item1,item2,item3,item4 */
    
    //查找元素的索引，如果包含特定元素，返回具体索引，否则返回：9223372036854775807
    NSLog(@"%ld",[array1 indexOfObject:@"item11"]);
    
    //是否包含特定元素
    NSLog(@"%i", [array1 containsObject:@"item1"] == TRUE ? 1 : 0);
    /* 1 */
    
    NSArray *subArray = [array1 subarrayWithRange:NSMakeRange(1, 2)];
    NSLog(@"%@",subArray);
    /*
     (
     item1,
     item2
     )
     */
    
    //保存数组元素到本地文件，以xml格式序列化存储
    [array1 writeToFile:@"/Users/new/Desktop/array.txt" atomically:YES];
    /*
     <?xml version="1.0" encoding="UTF-8"?>
     <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
     <plist version="1.0">
     <array>
     <string>item0</string>
     <string>item1</string>
     <string>item2</string>
     <string>item3</string>
     <string>item4</string>
     </array>
     </plist>
     */
    
    //读取本地文件，反序列化为数组
    NSArray *array2 = [[NSArray alloc]initWithContentsOfFile:@"/Users/new/Desktop/array.txt"];
    NSLog(@"%@",array2);
    /*
     (
     item0,
     item1,
     item2,
     item3,
     item4
     )
     */
    
    //判断数组元素是否相等
    BOOL result = [array1 isEqualToArray:@[@"item0",@"item1",@"item2"]];
    NSLog(@"%@",result);
    /* 0 */
}

• NSArray遍历

void arrayTest2()
{
    NSArray *array1 = [[NSArray alloc]initWithObjects:@"item0",@"item1",@"item2",@"item3",@"item4",nil];
    
    //遍历方法1
    for (int index = 0; index < array1.count; index++) {
        NSLog(@"%@",array1[index]);
    }
    /*
     item0
     item1
     item2
     item3
     item4
     */
    
    //遍历方法2
    for (NSString *item in array1) {
        NSLog(@"%@",item);
    }
    /*
     item0
     item1
     item2
     item3
     item4
     */
    
    //遍历方法3
    //NSEnumerator *enumerator = [array1 reverseObjectEnumerator]; //逆向遍历
    NSEnumerator *enumerator = [array1 objectEnumerator];          //正向遍历
    NSString *item = nil;
    while (item = [enumerator nextObject]) {
        NSLog(@"%@",item);
    }
    /*
     item0
     item1
     item2
     item3
     item4
     */
    
    //遍历方法4
    [array1 enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        NSLog(@"%ld = %@",idx,obj);
    }];
    /*
     0 = item0
     1 = item1
     2 = item2
     3 = item3
     4 = item4
     */
}

• NSArray排序

void arrayTest3()
{
    //排序方法1，普通比较器
    NSArray *array1 = @[@"1",@"21",@"11",@"5",@"51",@"3"];
    NSArray *array2 = [array1 sortedArrayUsingSelector:@selector(compare:)];
    NSLog(@"%@",array2);
    /*
     (
     1,
     11,
     21,
     3,
     5,
     51
     )
     */
    
    
    //排序方法2，代码块
    NSArray *array3 = [array1 sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        return [obj1 compare:obj2];
    }];
    NSLog(@"%@",array3);
    /*
     (
     1,
     11,
     21,
     3,
     5,
     51
     )
     */
    
    
    
    //排序方法3，自定义排序描述符
    NSArray *originalArray = @[
                                @{@"page_no":@"27",@"age":@24},
                                @{@"page_no":@"1", @"age":@23},
                                @{@"page_no":@"1", @"age":@21},
                                @{@"page_no":@"1", @"age":@25},
                                @{@"page_no":@"1", @"age":@15},
                                @{@"page_no":@"12",@"age":@19},
                                @{@"page_no":@"23",@"age":@29},
                                @{@"page_no":@"3", @"age":@22},
                                @{@"page_no":@"2", @"age":@30},
                                @{@"page_no":@"17",@"age":@33}
                            ];
    NSSortDescriptor *alphaNumSD = [NSSortDescriptor sortDescriptorWithKey:@"page_no" ascending:YES comparator:^NSComparisonResult(NSString *string1, NSString *string2) {
        return [string1 compare:string2 options:NSNumericSearch];
    }];
    NSSortDescriptor *dataNumSD = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES comparator:^NSComparisonResult(id data1, id data2) {
        return [data1 compare:data2];
    }];
    NSArray *sortedArray = [originalArray sortedArrayUsingDescriptors:@[alphaNumSD,dataNumSD]];
    NSLog(@"%@",sortedArray);
    /*
     (
     {
     age = 15;
     "page_no" = 1;
     },
     {
     age = 21;
     "page_no" = 1;
     },
     {
     age = 23;
     "page_no" = 1;
     },
     {
     age = 25;
     "page_no" = 1;
     },
     {
     age = 30;
     "page_no" = 2;
     },
     {
     age = 22;
     "page_no" = 3;
     },
     {
     age = 19;
     "page_no" = 12;
     },
     {
     age = 33;
     "page_no" = 17;
     },
     {
     age = 29;
     "page_no" = 23;
     },
     {
     age = 24;
     "page_no" = 27;
     }
     )
     */
    
    
    //排序方法4，自定义比较方法
    Person *person1 = [[Person alloc]initWithFirstName:@"hello" lastName:@"world" age:35];
    Person *person2 = [[Person alloc]initWithFirstName:@"abc" lastName:@"def" age:25];
    Person *person3 = [[Person alloc]initWithFirstName:@"cal" lastName:@"kdl" age:22];
    NSArray *personArray = @[person1,person2,person3];
    NSArray *tempArray = [personArray sortedArrayUsingSelector:@selector(comparePeople:)];
    NSLog(@"%@",tempArray);
    /*
     (
     " firstName: abc,lastName:def,age:25",
     " firstName: cal,lastName:kdl,age:22",
     " firstName: hello,lastName:world,age:35"
     )
     */
    
}

• NSMutableArray

　　NSMutableArray继承NSArray,所以NSArray的所有特性NSMutableArray都有，在此基础上,NSMutableArray主要新增了添加、删除、更新、插入等特性，如下代码演示：

void arrrayTest4()
{
    NSMutableArray *mutableArray = [[NSMutableArray alloc]initWithObjects:@"item0",@"item1",@"item2",@"item3",@"item4", nil];
    NSLog(@"%@",mutableArray);
    /*
     (
     item0,
     item1,
     item2,
     item3,
     item4
     )
     */
    
    //添加元素
    [mutableArray addObject:@"item5"];
    NSLog(@"%@",mutableArray);
    /*
     (
     item0,
     item1,
     item2,
     item3,
     item4,
     item5
     )
     */
    
    //插入元素
    [mutableArray insertObject:@"inserted item" atIndex:(NSInteger)1];
    NSLog(@"%@",mutableArray);
    /*
     (
     item0,
     "inserted item",
     item1,
     item2,
     item3,
     item4,
     item5
     )
     */
    
    //删除元素
    [mutableArray removeObject:@"item5"];
    NSLog(@"%@",mutableArray);
    /*
     (
     item0,
     item1,
     item2,
     item3,
     item4
     )
     */
    
    //更新元素
    [mutableArray replaceObjectAtIndex:(NSInteger)5 withObject:@"replacedItem"];
    NSLog(@"%@",mutableArray);
    /*
     (
     item0,
     "inserted item",
     item1,
     item2,
     item3,
     replacedItem
     )
     */
    
    //删除所有元素
    [mutableArray removeAllObjects];
    NSLog(@"%ld",mutableArray.count);
    /* 0 */
}