NSArray & NSMutableArray
一、不可变数组NSArray
1 使用arrayWithObjects创建NSArray
NSArray *arr = [NSArray arrayWithObjects:@"abc",@"def",@"123",nil];
// NSArray *arr = [[NSArray alloc] initWithObjects:@"111",@"ddd",@"234",nil];
2 使用arrayWithArray创建NSArray
NSArray *arr1 = [NSArray arrayWithArray:arr];
// NSArray *arr1 = [[NSArray alloc]initWithArray:arr];
3 使用@创建NSArray,只能创建不可变数组
NSArray *arr2 = @[@"aaaa",@"bbb",@"ddddd"];
NSLog(@"arr2 = %@",arr2);
4 返回元素个数
NSLog(@"arr2 count = %ld",[arr2 count]);
5 返回指定位置id
NSString *str0 = [arr2 objectAtIndex:2];
NSLog(@"str0 = %@",str0);
6 访问数组的最后一个元素
NSString *str = [arr2 lastObject];
NSLog(@"str = %@",str);
7 访问数组的第一个元素
NSString *str1 = [arr firstObject];
NSLog(@"str1 = %@",str1);
8 判断数组内是否含有某一个对象
if([arr containsObject:@"123"]) {
NSLog(@"含有此对象");
}
9 获取某个对象在数组中的下标值
NSUInteger index = [arr indexOfObject:@"123"];
10 数组的遍历
for(NSInteger i =0;i < [arr count]; i++) {
NSLog(@"arr[%ld] = %@",i,arr[i]);
}
11 快速枚举法(快速遍历)
for(id obj in arr) {
NSLog(@"obj = %@",obj);
}
二、可变数组NSMutableArray
1 实例化一个空的可变数组
NSMutableArray *nsarr = [[NSMutableArray alloc]init];
//NSMutableArray *aa1Group=[NSMutableArray arrayWithCapacity:5];
2 添加一个元素
[nsarr addObject:@"ONE"];
NSLog(@"nsarr = %@",nsarr);
3 添加多个元素
[nsarr addObjectsFromArray:@[@"ONE",@"TWO",@"THREE"]];
NSLog(@"nsarr = %@",nsarr);
4 插入元素
[nsarr insertObject:@"Two" atIndex:1];
NSLog(@"nsarr = %@",nsarr);
5 替换元素
[nsarr replaceObjectAtIndex:0 withObject:@"1"];
NSLog(@"nsarr = %@",nsarr);
6 查询元素
NSString *result = [nsarr objectAtIndex:1];//arr[1]
NSLog(@"result = %@",result);
7 删除指定元素
[nsarr removeObject:@"ONE"];
NSLog(@"nsarr = %@",nsarr);
8 删除指定下标的元素
[nsarr removeObjectAtIndex:2];
NSLog(@"nsarr = %@",nsarr);
9 删除最后一个元素
[nsarr removeLastObject];
NSLog(@"nsarr = %@",nsarr);
10 删除所有元素
[nsarr removeAllObjects];
NSLog(@"nsarr = %@",nsarr);
11 删除数组中含有的所有元素
[nsarr removeObjectsInArray:@[@"1",@"THREE"]];
12 交换元素
NSMutableArray *nsarr1 = [NSMutableArray arrayWithObjects:@"1",@"2",@"3",nil];
[nsarr1 exchangeObjectAtIndex:1 withObjectAtIndex:2];
NSLog(@"nsarr1 = %@",nsarr1);
13 切割字符串
NSString *str3 = @"I am a super man + beautiful, yeah!";
14 用指定的字符串进行切割
NSArray *rArr = [str3 componentsSeparatedByString:@" "];
NSLog(@"rArr = %@",rArr);
15 实例化一个字符集合
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@" ,+"];
16 按照字符集合所提供的字符进行切割
NSArray *rArr2 = [str3 componentsSeparatedByCharactersInSet:set];
NSLog(@"rArr2 = %@",rArr2);
17 拼接数组内的字符串
NSString *str2 = [rArr2 componentsJoinedByString:@"-"];
NSLog(@"str2 = %@",str2);
18 按照ASCII码大小进行排序,SEL:方法选择器(储存一个方法名)
NSMutableArray *arr3 = [NSMutableArray arrayWithObjects:@"B",@"A",@"C",@"Z",nil];
[arr3 sortedArrayUsingSelector:@selector(compare:)];//方法选择器
19 按三个人年龄大小排序
Person *per0 = [[Person alloc]initWith:18];
Person *per1 = [[Person alloc]initWith:6];
Person *per2 = [[Person alloc]initWith:60];
NSMutableArray *perArr = [[NSMutableArray alloc]initWithObjects:per0,per1,per2,nil];
//compareAge提供一个排序方法，看按什么方式排序
NSArray *resultPerArr = [perArr sortedArrayUsingSelector:@selector(compareAge:)];