swift基础-4-数组

数组定义:
OC:
有值数组

NSArray *arr0 = @[@1, @2, @3];
NSArray *arr1 = [NSArray arrayWithObjects:@1, @2, @3, nil];
NSLog(@"%@", arr1);

空数组

NSArray *arr2 = @[];
NSArray *arr3 = [NSArray array];
NSLog(@"%@", arr3);

不可变数组:NSArray
可变数组:NSMutableArray

swift:
有值数组

var arr0 = [1, 2, 3]
var arr1: Array = [1, 2, 3]
var arr2: Array = [1, 2, 3]
var arr3: [Int] = [1, 2, 3]
//var arr4: Int[] = [1, 2, 3] 早期写法

空数组

var arr5 = []
var arr6 = [Int]()
var arr7 = Array()
print(arr7)

可变数组:

var arr8 = []

不可变数组:

let arr9  = []

元素类型
OC:

NSArray *arr = @[@1, @"solozyx", @1.72];
NSLog(@"%@", arr);

swift:

var arr10 = [1, "solozyx", 1.72]
print(arr10)

如果想明确表示数组中存放的是不同类型的数据, 可以使用Any关键字, 表示数组中可以存放不同类型的数据

var arr11:Array = [1, "solozyx", 1.72]
print(arr11)

数组操作
1.获取长度
OC:

NSArray *arr = @[@1, @2, @3];
NSLog(@"%tu", arr.count);

swift:

var arr12 = [1, 2, 3]
print(arr12.count)

2.判断是否为空
OC:

NSArray *arr = @[];
NSLog(@"%d", arr.count != 0);

swift:

var arr13 = [1, 2, 3]
print(arr13.isEmpty)

3.检索
OC:

NSArray *arr = @[@1, @2, @3];
NSLog(@"%@", arr[0]);

swift:

var arr14 = [1, 2, 3]
print(arr14[0])

4.追加
OC:

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
[arr addObject:@4];
NSLog(@"%@", arr);

swift:

var arr15 = [1, 2, 3]
arr15.append(4);
print(arr15)

var arr16 = [1, 2, 3]
arr16 += [4]
// arr16 += 4 以前的版本可以这样写
// arr16 += [5, 6, 7]
arr16 += arr16[0...1] // 还可以自己搞自己
print(arr16)

5.插入
OC:

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
[arr insertObject:@4 atIndex:0];
NSLog(@"%@", arr);

swift:

var arr17 = [1, 2, 3]
arr17.insert(4, atIndex: 0);
print(arr17)

6.更新
OC:

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
arr[0] = @8;
NSLog(@"%@", arr);

swift:

var arr18 = [1, 2, 3]
arr18[0] = 8
print(arr18)

7.删除
OC:

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
[arr removeObject:@1];
NSLog(@"%@", arr);

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
[arr removeLastObject];
NSLog(@"%@", arr);

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
[arr removeAllObjects];
NSLog(@"%@", arr);

swift:

var arr19 = [1, 2, 3]
arr19.removeAtIndex(0)
print(arr19)

var arr20 = [1, 2, 3]
arr20.removeLast()
print(arr20)

var arr21 = [1, 2, 3]
arr21.removeAll(keepCapacity: false) //是否保持容量, 如果为true, 即便删除了容量依然存在, 容量是2的倍数
print(arr21)
print(arr21.capacity)
//注意: 如果数组是一个不可变数组不能更新/插入和删除

Range
OC:

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
[arr removeObjectsInRange:NSMakeRange(0, 2)];
NSLog(@"%@", arr);

swift:

var arr22 = [1, 2, 3]
arr22.removeRange(Range(start: 1, end: 2))
print(arr22)

var arr23 = [1, 2, 3]
arr23.removeRange(0...0)
print(arr23)

Range就是半闭区间

var range = 0...5
//range = 99 // 通过报错可以推断出类型
print(range)   // 通过打印也可以推断出类型

var range1:Range = 0...5
//var range2:Range; // 必须遵守ForwardIndexType协议
// start 起点 end 终点
var range3:Range = Range(start: 0, end: 5)
var range4:Range = 0..<5 
print(range1)
print(range3)
print(range4)

数组的批量操作
OC:

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
NSRange range = NSMakeRange(0, 2);
// [arr replaceObjectsInRange:range withObjectsFromArray:@[@99, @88]];
[arr replaceObjectsInRange:range withObjectsFromArray:@[@99, @88, @77, @66]];
NSLog(@"%@", arr);

swift:

var arr = [1, 2, 3]//[1, 2, 3]
arr[0...1] = [99, 88]
arr//[99, 88, 3]

arr[0...1] = [99, 88, 77, 66]
arr//[99, 88, 77, 66, 3]

// :( 注意这行 等价于上一行代码 
arr.replaceRange(Range(start: 0, end: 2), with: [99, 88, 77, 66])
arr//[99, 88, 77, 66, 77, 66, 3]

arr.replaceRange(1..<2, with: [99, 88, 77, 66])
arr//[99, 99, 88, 77, 66, 77, 66, 77, 66, 3]

遍历
OC:

NSArray *arr = @[@1, @2, @3];
for (int i = 0; i < arr.count; i++) {
    NSLog(@"%@", arr[i]);
}

for (NSNumber *number in arr) {
    NSLog(@"%@", number);
}

swift:

var arr1 = [1, 2, 3]
for var i = 0 ; i < arr1.count ; i++
{
    print(arr1[i])
}

for number in arr1
{
    print(number)
}

for i in 0..

取出数组中某个区间范围的值

var arr2 = [1, 2, 3]
for number in arr2[0..<3]
{
    print(number) // 1 2 3 
}

for number in arr2[0...2]
{
    print(number) // 1 2 3 
}