NSMutableArray （可變數(shù)組）繼承NSArry（不可變數(shù)組）

1.創(chuàng)建對象的方式

1.1初始化方式

    NSMutableArray *array = [[NSMutableArray alloc]initWithCapacity:10];

1.2遍歷構造器

    NSMutableArray *array1 =[NSMutableArray arrayWithCapacity:10];

1.3字面量

    NSMutableArray *array2 =[@[@"aa",@"bb"]mutableCopy];

2.添加元素

2.1直接添加元素

   [array addObject:@"zhangsan"];
    NSLog(@"array = %@",array);// array = zhangsan

   [array addObject:@"wangwu"];
    NSLog(@"array = %@",array);
    /*array = (
     zhangsan,
     wangwu
     )
     */

2.2指定位置交通添加

     //在下標是1的地方添加zhaoliu
    [array insertObject:@"zhaoliu" atIndex:1];
    NSLog(@"array = %@",array);
    /*數(shù)組是從0開始算起
     array = (
     zhangsan,
     zhaoliu,
     wangwu
     )
     */
   
   //在下標是3的地方添加zhangsan
   [array insertObject:@"zhangsan" atIndex:3];
    NSLog(@"array = %@",array);
    /*(
     zhangsan,
     zhaoliu,
     wangwu,
     zhangsan
     )*/

3.刪除

3.1移除所有zhangsan的元素

    [array removeObject:@"zhangsan"];
    NSLog(@"array = %@",array);
    /*(
     zhaoliu,
     wangwu
     )*/

3.2移除下標是1的元素

    [array removeObjectAtIndex:1];
    NSLog(@"array = %@",array);
    /*(
     zhaoliu
     )*/

3.3移除最后一個元素

    [array removeLastObject];

3.4//移除所有元素（刪除后數(shù)組為空）

    [array removeAllObjects];

給數(shù)組添加元素

    [array addObject:@"zhangsan"];
    [array addObject:@"lisi"];
    [array addObject:@"wangwu"];
    [array addObject:@"zhangsan"];
    NSLog(@"array = %@",array);
    /*array = (
     zhangsan,
     lisi,
     wangwu,
     zhangsan
     )*/

3.4移除某一個范圍

    [array removeObjectsInRange:NSMakeRange(1,3)];
    NSLog(@"array = %@",array);
    /*array = (
     zhangsan
     )*/
    //移除某一個范圍后面的元素
    //[array removeObject:@"zhangsan"inRange:NSMakeRange(1, 3)];

給數(shù)組添加元素

    [array addObject:@"lisi"];
    [array addObject:@"wangwu"];
    [array addObject:@"zhaoliu"];
    NSLog(@"array = %@",array);
    /*array = (
     zhangsan,
     lisi,
     wangwu,
     zhaoliu
     )*/

4.交換指定位置上的兩個元素

    [array exchangeObjectAtIndex:0 withObjectAtIndex:2];
    NSLog(@"array1 = %@",array);
    /* (
     wangwu,
     lisi,
     zhangsan,
     zhaoliu
     )*/

5.替換數(shù)組中的一個元素

    [array replaceObjectAtIndex:3 withObject:@"xueren"];
    NSLog(@"array2 = %@",array);
    /* (
     wangwu,
     lisi,
     zhangsan,
     xueren
     )*/

For循環(huán)里面不允許去更改數(shù)組的長度,但是移除最后一個元素不影響數(shù)組的運行

    //如果刪除lisi 數(shù)組的長度就會改變從而崩潰
    for (NSString *str in array) {
        if ([str isEqualToString:@"xueren"]) {
            [array removeObject:@"xueren"];
        
        }
    }
    NSLog(@"%@",array);
        /*(
     lisi,
     zhaoliu
     )*/