iOS Swift 基础二

1.

/*

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

*/

//有值数组

var arr0 = [1,2, 3]

var arr1: Array = [1,2, 3]

var arr2: Array<Int> = [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<Int>()

print(arr7)

//不可变数组:

var arr8 = []

//可变数组:

let arr9  = []

/*

元素类型

OC:

NSArray *arr = @[@1, @"lnj", @1.75];

NSLog(@"%@", arr);

*/

var arr10 = [1,"lnj", 1.75]

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<Any> = [1,"lnj", 1.75]

print(arr11)

/*

数组操作

1.获取长度

OC:

NSArray *arr = @[@1, @2, @3];

NSLog(@"%tu", arr.count);

*/

var arr12 = [1,2, 3]

print(arr12.count)

/*

2.判断是否为空

OC:

NSArray *arr = @[];

NSLog(@"%d", arr.count != 0);

*/

var arr13 = [1,2, 3]

print(arr13.isEmpty)

/*

3.检索

OC:

NSArray *arr = @[@1, @2, @3];

NSLog(@"%@", arr[0]);

*/

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);

*/

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);

*/

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);

*/

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);

*/

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

//第一个版本的不可变数组是可以修改的

/*

Range

OC:

NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];

[arr removeObjectsInRange:NSMakeRange(0, 2)];

NSLog(@"%@", arr);

*/

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)

// 其实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)// 通过答应也可以推断出类型

var range1:Range<Int> =0...5

//var range2:Range<String>; // 必须遵守ForwardIndexType协议

// start 起点 end终点

var range3:Range<Int> =Range(start: 0, end:5)

var range4:Range<Int> =0..<5 

print(range1)

print(range3)

print(range4)

2.数组的运算

/*

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);

*/

var arr = [1,2, 3]

//arr[0...1] = [99, 88]

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

// 等价于上一行代码

//arr.replaceRange(Range(start: 0, end: 2), with: [99, 88, 77, 66])

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

print(arr)

/*

4.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);

}

*/

var arr1 = [1,2, 3]

for var i =0 ; i < arr1.count ; i++

{

    print(arr1[i])

}

for number inarr1

{

    print(number)

}

for i in 0..<arr1.count

{

    print(arr1[i])

}

// 取出数组中某个区间范围的值

var arr2 = [1,2, 3]

for number inarr2[0..<3]

{

    print(number)

}