c++ - Qt5中如何 "merge"两个QVariantMap的内容？

Question

我有两个 QVariantMap 实例 A 和 B。

在 A 中，我有以下字符串:[ "key1"=> "Cat", "key2"=> "Dog", "key3"=> "Mouse"]。在 B 中，我有以下字符串:[ "key1"=> "Cat", "key4"=> "Dog", "key3"=> "Bison"] .

我想将它们合并到第三个 QVariantMap 实例 C 中，以便它包含以下内容:

[ "key1"=> "Cat", "key2"=> "Dog", "key3"=> "Bison", "key4"=> "Dog"].

请注意只有一只“猫”以及“老鼠”是如何被“野牛”取代的。

有没有一种方法可以在 Qt5 中执行此操作而无需编写我自己的实用程序函数来执行此操作？

Answer 1

QVariantMap A;
QVariantMap B;
QVariantMap C;
A.insert("key1", "Cat");
A.insert("key2", "Dog");
A.insert("key3", "Mouse");

B.insert("key1", "Cat");
B.insert("key4", "Dog");
B.insert("key3", "Bison");

//Merge A and B
C = A.unite(B);
//C.value("key1") = "Cat" 
//C.value("key3") = "Bison"
//C.values("key3") = {"Bison", "Mouse"}
//C.values("key1") = {"Cat", "Cat"}
//Note: A = C as well. If you don't want to change the value of A, then assign a temporary value to A or create a copy of A

//Method 1: Create a copy of A
QVariantMap ACopy = A;
C = ACopy.unite(B);

//Method 2: Create a temporary variable that hold A value:
QVariantMap ATemp = A;
C = A.unite(B);
A = ATemp;