Question

我有一个值数组，例如a = [1,2,3]和字典数组b = [{{2：“ a”}，{3：“ b”}，{45：“ r”} ，{16：“ a”}]。我如何从b中获取与数组中的值匹配的键的值。有人可以给我提示吗？谢谢。

Answer 1

在objective-c中

NSMutableArray *c = [[NSMutableArray alloc] init];

for (NSNumber *i in a) {
    BOOL iFound = NO;
    for (NSDictionary *dict in b) {
        if ((NSNumber *)[[dict allKeys] firstObject] == i) {
            iFound = YES;
            [c addObject:(NSString *)[[dict allValues] firstObject]];
        }
    }
    if (!iFound) {
        [c addObject: [NSNull null]];
    }
}
NSLog(@"%@",c);//("<null>",a,b)

迅速

let a = [1,2,3]
let b = [[2:"a"],[3:"b"],[45:"r"],[16:"a"]]
let c = a.map { i in b.first(where: { $0.keys.first == i })?.values.first }
print(c)//[nil, Optional("a"), Optional("b")]

从字典数组中获取键值

1 个答案: