OC学习NSArray与NSMutableArray数组

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@autoreleasepool {
//创建数组对象，NSArray不可变数组
//c语言的数组可以存放任何类型的数据，同一个数组只能有同一种数据类型
//oc语言的数组只能存放对象，可以存放任意对象
// [NSNull null] == 空对象
//NSArray *arr = [[NSArray alloc] initWithObjects:@"123",@"345",@"abc", nil];
NSArray *arr1 = @[@"1 2 3", @"345", [NSNull null], @"789"];
NSArray *arr3 = [[NSArray alloc] initWithArray:arr1];
NSLog(@"arr = %@",arr3);
//将c数组转换为oc数组对象
//oc不允许将nil插入到数组中,因为nil作用是数组的结束标记
NSString *carr[10] = {@"123", @"456", @"789"};
NSArray *arr4 = [[NSArray alloc] initWithObjects:carr count:2];
NSLog(@"arr4 = %@",arr4);
//获取元素个数
NSUInteger count = [arr4 count];
NSLog(@"count = %ld",count);
//获取指定下标元素
NSLog(@"%@",[arr3 objectAtIndex:1]);
//获取第一个元素或者最后一个元素
id arrf = [arr3 firstObject];
id arrl = [arr3 lastObject];
NSLog(@"%@ %@",arrf,arrl);
//获取子集
NSArray *arr2 = @[@"111", @"222", @"333", @"444", @"555", @"666"];
//取出连续范围的元素作为子集内容
NSArray *sub1 = [arr2 subarrayWithRange:NSMakeRange(1, 3)];
NSLog(@"sub1 = %@", sub1);
//获取任意元素作为子集
//1.列出所需要元素的下标清单
NSMutableIndexSet *indexs = [NSMutableIndexSet indexSet];
//1-1.将要获取元素的下标写入清单
for (NSInteger i = 0; i < [arr2 count]; i++)
{
if (i % 2 != 0)
{
[indexs addIndex:i];
}
}
//2.将清单交给数组
//id obj =[arr2 objectAtIndex:0]; //获取单个元素,返回单个元素
NSArray *sub2 = [arr2 objectsAtIndexes:indexs];//获取下标清单里的所有元素,返回一个元素集合(数组)
NSLog(@"sub2 = %@", sub2);
//获取最长字符串和最小字符串
//快速枚举
NSArray *arr5 = @[@"123456789", @"222", @"333", @"errr", @"444", @"5", @"666"];
NSInteger maxLength = [arr5[0] length];
NSInteger minLength = [arr5[0] length];
NSString *maxString = nil;
NSString *minString = nil;
for (id obj in arr5) {
if (maxLength <= [obj length]) {
maxLength = [obj length];
maxString = obj;
}
if (minLength >= [obj length]) {
minLength = [obj length];
minString = obj;
}
}
NSLog(@"maxString = %@, minString = %@",maxString,minString);
#if 0
//创建可变数组对象
NSMutableArray *arr1 = [[NSMutableArray alloc] initWithCapacity:30];
NSMutableArray *arr2 = [NSMutableArray arrayWithCapacity:30];
//添加元素
[arr1 addObject:@"123"];
[arr1 addObject:@"456"];
[arr2 addObjectsFromArray:arr1];
[arr2 addObject:@"789"];
[arr2 addObject:@"789"];
[arr2 addObject:@"789"];
NSLog(@"arr1 = %@",arr1);
NSLog(@"arr2 = %@",arr2);
//插入元素
//插入下标的范围: 0<=index<=count
[arr1 insertObject:@"aaa" atIndex:1];
[arr1 insertObject:@"bbb" atIndex:[arr1 count]];
NSLog(@"arr1 = %@",arr1);
//删除
[arr2 removeAllObjects];//删除所有元素
[arr2 removeLastObject];//删除最后一个元素
[arr2 removeObject:@"789"];//删除指定对象，会将所有对象删除
[arr2 removeObject:@"789" inRange:NSMakeRange(1, 2)];//删除指定范围中的指定对象
[arr2 removeObjectAtIndex:0];//删除指定下标的元素
[arr2 removeObjectsInRange:NSMakeRange(2, 2)];//删除指定范围中得元素
[arr2 removeObjectIdenticalTo:@"789"];
[arr2 removeObjectIdenticalTo:@"789" inRange:NSMakeRange(2, 1)];
//如果要删除不连续的元素，则先把要删除的元素放在一个清单中，然后再删除该清单
//比如要删下标为偶数的
NSMutableIndexSet *indexs = [NSMutableIndexSet indexSet];
for (int i = 0; i < [arr2 count]; i++) {
if (i % 2 == 0) {
[indexs addIndex:i];
}
}
//删除清单中得元素
[arr2 removeObjectsAtIndexes:indexs];
//修改数组中得内容
[arr2 replaceObjectAtIndex:2 withObject:@"aaa"];
NSArray *arr = @[@"qqqq",@"www",@"ee"];
[arr2 replaceObjectsAtIndexes:indexs withObjects:arr];
// qq, 789, ww, 456, ee
[arr2 replaceObjectsInRange:NSMakeRange(1, 3) withObjectsFromArray:arr];// qq, qq, ww, ee, ee,在指定范围内，修改数组中得内容。
//交换数组中得内容
[arr2 exchangeObjectAtIndex:1 withObjectAtIndex:3];
//用oc对c语言中得数组进行排序
for (int i = 0; i < [arr2 count]; ++i) {
for (int j = i + 1; j < [arr2 count]; ++j) {
if ([arr2[i] length] > [arr2[j] length]) {
[arr2 exchangeObjectAtIndex:i withObjectAtIndex:j];
}
}
}
NSLog(@"arr2 = %@",arr2);
#endif

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