OC系列foundation Kit基础－NSMutableArray

一.可变数组创建和不可变数组类似

二.可变数组操作

首先我们创建一个空的可变数组

NSMutableArray *mArr = [[NSMutableArray alloc]init];

1.添加元素

[mArr addObject:@"one"];
[mArr addObject:@"two"];
[mArr addObject:@"three"];
        
NSLog(@"mArr is %@",mArr);

输出结果:

2016-06-27 16:06:54.676 OcTest[964:728178] mArr is (
    one,
    two,
    three
)
Program ended with exit code: 0

2.删除元素

[mArr removeObject:@"one"];
[mArr removeAllObjects];

3.置换元素

[mArr exchangeObjectAtIndex:0 withObjectAtIndex:2];

三.应用实例:将字符串拆分成数组反向输出

NSString *str = @"this is an Object-C program";
NSArray *arr = [str componentsSeparatedByString:@" "];
NSMutableArray *mArr = [[NSMutableArray alloc]init];
NSEnumerator *enu = [arr reverseObjectEnumerator];
id obj;
while(obj = [enu nextObject]){
   [mArr addObject:obj];
}
NSLog(@"mArr is %@",mArr);

　　输出结果:

2016-06-27 16:16:45.198 OcTest[992:754324] mArr is (
    program,
    "Object-C",
    an,
    is,
    this
)
Program ended with exit code: 0