Question

将数组中前三个对象（或者数组有多大的1或2）转换为以逗号分隔的字符串的最有效方法是什么。我觉得有一种方法可以解决这个问题，但我无法解决这个问题

对象是Bands，存储在bandArray中，每个band的属性包含bandName。

所以输出就像

String
"Abba"                    <- when there is one object
"Abba, Kiss"              <- when there is two objects
"Abba, Kiss, Nirvana"     <- when there is three objects
"Abba, Kiss, Nirvana"     <- when there is four objects. after three, names are ignored

Answer 1

您可以使用subarrayWithRange:：

NSString *res = [[[theArray subarrayWithRange:NSMakeRange(0, fmin(3, [theArray count]))] 
                  valueForKey:@"brandName"] 
                 componentsJoinedByString:@", "];

Answer 2

NSUInteger count = [bandArray count];
if (count > 3){
    count = 3;
}
NSString * resultString = [[bandArray subarrayWithRange:NSMakeRange(0,count)]  componentsJoinedByString:@", "];

Answer 3

您可以尝试以下操作（虽然它完全未经测试，因为我远离我的Mac ）

int bandCount = 1;
NSString *bands;
for (NSString *band in bandArray) {
    if (bandCount > 3) break;
    if (bandCount == 1) {
        bands = [NSString stringWithFormat:@"%@", band];
    } else {        
        bands = [NSString stringWithFormat:@"%@, %@", bands, band];
    }
    bandCount ++;
}

Answer 4

可能不是最快但最简单的，谁知道苹果苹果在创建子阵列时可能会做一些聪明的事。

[[array subarrayWithRange:NSMakeRange(0,MIN(array.length,3)] componentsJoinedByString:@","];

NSArray的前三项成为NSString？

4 个答案: