从数组中获取随机对象

Question

我想从数组中获得随机对象，有没有什么办法可以从可变数组中找到随机对象？

Answer 1

@interface NSArray (Random) 
- (id) randomObject; 
@end 

@implementation NSArray (Random) 

- (id) randomObject 
{ 
    if ([self count] == 0) { 
     return nil; 
    } 
    return [self objectAtIndex: arc4random() % [self count]]; 
} 

@end 

Answer 2

id obj;  
int r = arc4random() % [yourArray count]; 
    if(r<[yourArray count]) 
     obj=[yourArray objectAtIndex:r]; 
    else 
    { 
    //error message 
    } 

Answer 3

id randomObject = nil; 
if ([array count] > 0){ 
    int randomIndex = arc4random()%[array count]; 
    randomObject = [array objectAtIndex:randomIndex]; 
} 

Answer 4

最好的办法是做这样的事情

int length = [myMutableArray count]; 
// Get random value between 0 and 99 
int randomindex = arc4random() % length; 

Object randomObj = [myMutableArray objectAtIndex:randomindex]; 

Answer 5

如果你不想延长的NSArray这将在一个给定的阵列得到一个随机值一行：

id randomElement = [myArray objectAtIndex:(arc4random() % myArray.count)]; 

Answer 6

Just Copy和粘贴

-(NSMutableArray*)getRandomValueFromArray:(NSMutableArray*)arrAllData randomDataCount:(NSInteger)count { 
NSMutableArray *arrFilterData = [[NSMutableArray alloc]init]; 
for(int i=0; i<count; i++){ 

    NSInteger index = arc4random() % (NSUInteger)(arrAllData.count); 
    [arrFilterData addObject:[arrAllData objectAtIndex:index]]; 
    [arrAllData removeObjectAtIndex:index]; 
} 
return arrFilterData; 
} 

注：数=要获取

Answer 7

这里随机值的数量是使用在阵列的扩展迅速解决：

extension Array { 
    func sample() -> Element? { 
     if self.isEmpty { return nil } 
     let randomInt = Int(arc4random_uniform(UInt32(self.count))) 
     let randomIndex = self.startIndex.advancedBy(randomInt) 
     return self[randomIndex] 
    } 
} 

你可以用它像这样简单：

let digits = Array(0...9) 
digits.sample() // => 6 

---

如果你喜欢一个框架也有一些更方便的功能，然后结帐HandySwift。您可以通过迦太基将其添加到您的项目然后用它完全像上面的例子：

import HandySwift  

let digits = Array(0...9) 
digits.sample() // => 8