iphone - 从另一个 NSDictionary 创建 NSDictionary？

Question

我有一个 NSDictionary 记录这个:

    address = "30 East 23rd Street";
    address1 = "30 East 23rd Street";
    address2 = "";
    age = 32;
    alert = "";
    "blood_pressure_1" = "";
    "blood_pressure_2" = "";
    bmi = "";

我想创建一个新的 NSDictionary，它只包含旧的几个键，例如 age、bmi 和 alert。我该怎么做？

Answer 1

这可能更容易一些:

NSArray *keys = [NSArray arrayWithObjects:@"address", @"address1", @"address2", nil];
NSDictionary *subset = [NSDictionary dictionaryWithObjects:
    [fullDictionary objectsForKeys:keys notFoundMarker:@""]
    forKeys:keys];