ios - NSMutableDictionary 比较提取不等于对

Question

我有两个 NSMutableDictionay，我们将预期的一个称为“A”，将操作结果的一个称为“B”

我想将“A”和“B”之间的差异插入“C”NSMutableDictionary。

我使用 if (![dicExpected isEqualToDictionary:actualDic]) {


但是获得非常见对的最佳方法是什么？

Answer 1

该问题包含一些含糊之处。我认为其意图可能是假设这两个词典具有匹配的键并输出“b”词典值作为差异。下面的代码执行此操作，但考虑了其他解释:

// use the keys in dA to find non-matching values in dB

- (NSDictionary *)nonMatching:(NSDictionary *)dA comparedTo:(NSDictionary *)db {

    NSMutableDictionary *diff = [NSMutableDictionary dictionary];

    for (id key in [dA allKeys]) {
        id valueA = dA[key];
        id valueB = dB[key];
        if (valueB && ![valueA isEqual:valueB]) {

            // here, the question is ambiguous. what should go in the output
            // for non-matching values? the b value? both?
            // both would look like this:  diff[key] = @[valueA, valueB];
            // but lets guess that you want just the b value

            diff[key] = valueB;
        }
        // another ambiguity in the question is what to do with keys in the dA that
        // don't appear in dB.  One idea is to ignore them, which is what happens here
        // without more code.  that's probably what you need.  anther idea would
        // be to record a null in the output for those, like this:
        // if (!valueB) diff[key] = [NSNull null];
    }

    // the last ambiguity is dealing with dB keys that don't appear in dA
    // again, do nothing is probably the idea you're looking for, but this would work, too:

    // for (id keyB in [dB allKeys]) {
    //     if (!dA[keyB]) diff[keyB] = dB[keyB];
    // }

    return diff;
}