數組的基本使用
/*
數組定義:
OC:
有值數組
NSArray *arr0 = @[@1, @2, @3];
NSArray *arr1 = [NSArray arrayWithObjects:@1, @2, @3, nil];
NSLog(@"%@", arr1);
空數組
NSArray *arr2 = @[];
NSArray *arr3 = [NSArray array];
NSLog(@"%@", arr3);
不可變數組:NSArray
可變數組:NSMutableArray
*/
//有值數組
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] // 早期寫法 已廢棄
//空數組
//var arr5 = [] // 已廢棄
var arr6 = [Int]()
var arr7 = Array<Int>()
print(arr7)
//不可變數組
let arr8 : [Int] = []
//可變數組
var arr9 : [String] = [String]()
/*
元素類型
OC:
NSArray *arr = @[@1, @"lnj", @1.75];
NSLog(@"%@", arr);
*/
var arr10 = [1,"hjq",1.65] as [Any]
print(arr10)
print(arr10[2])
// 打印結果: [1, "hjq", 1.6499999999999999]
// 1.65
//如果想明確表示數組中存放的是不同類型的數據, 可以使用Any關鍵字, 表示數組中可以存放不同類型的數據
var arr11:Array<Any> = [1,"hjq",1.75]
print(arr11)
print(arr11[2])
// 打印結果: [1, "hjq", 1.75]
// 1.75
/*
數組操作
1.獲取長度
OC:
NSArray *arr = @[@1, @2, @3];
NSLog(@"%tu", arr.count);
*/
var arr12 = [1,2,3]
print(arr12.count)
/*
2.判斷是否為空
OC:
NSArray *arr = @[];
NSLog(@"%d", arr.count != 0);
*/
var arr13 = [1,2,3]
print(arr13.isEmpty)
/*
3.檢索
OC:
NSArray *arr = @[@1, @2, @3];
NSLog(@"%@", arr[0]);
*/
var arr14 = [1,2,3,4]
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]
print(arr16)
arr16 += arr16[0...1] // 也可以借助自己數組元素追加
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, at: 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] = 0
print(arr18)
/*
7.刪除
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.remove(at: 0)
print(arr19)
var arr20 = [1,2,3,4]
arr20.removeLast()
print(arr20)
var arr21 = [1,2,3,4]
arr21.removeFirst()
print(arr21)
var arr22 = [1,2,3,4]
arr22.removeAll(keepingCapacity: true) // 是否保持容量, 如果為true, 即使刪除了容量依然存在, 容量是2的倍數
print(arr22)
print(arr22.capacity)
//註意: 如果數組是一個不可變數組不能更新/插入和刪除
//第一個版本的不可變數組是可以修改的
/*
Range
OC:
NSMutableArray *arr = [NSMutableArray arrayWithObjects:@1, @2, @3, nil];
[arr removeObjectsInRange:NSMakeRange(0, 2)];
NSLog(@"%@", arr);
*/
//移除某區間位置的數組元素
var arr23 = [1,2,3]
//arr22.removeRange(Range(start: 0, end: 1)) 2.0寫法 已廢棄
arr23.removeSubrange(0...1)
print(arr23)
var arr24 = [1,2,3]
arr24.replaceSubrange(0..<1, with: [8])
print(arr24)
// 其實Range就是半閉區間
var range = 0...5
//range = 99 // 通過報錯可以推斷出類型
print(range) // 通過答應也可以推斷出類型
/// 這個知識點需要再探索一次 range
//var range1:Range<Int> = 0...5
//var range2:Range<String>; // 必須遵守ForwardIndexType協議
// start 起點 end 終點
//var range3:Range<Int> = Range(start: 0, end: 5)
//var range4:Range<Int> = 0..<5
//print(range3)
//print(range4)
/*
數組的批量操作
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] = [99,98]
//arr[0...1] = [99,88,77]
//等價於上一行代碼
arr.replaceSubrange(0...1, with: [99,88,77])
print(arr)
/*
4.遍歷
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]
// 2.0
//for var i = 0 ; i < arr1.count ; i++
//{
// print(arr1[i])
//}
// 3.0
for i in 0..<arr1.count
{
print(arr1[i])
}
for number in arr1
{
print(number)
}
//取出數組中某個區間範圍的值
var arr2 = [1,2,3]
for number in arr2[0..<3]
{
print(number)
}
數組的基本使用