[英]How to concatenate two TStringDynArray?
Is there a way to concatenate the content of one TStringDynArray
to another TStringDynArray
?有没有办法将一个
TStringDynArray
的内容连接到另一个TStringDynArray
?
//First TStringDynArray
Item1
Item2
Item3
//Second TStringDynArray
ItemA
ItemB
ItemC
//Result after concatenate
Item1
Item2
Item3
ItemA
ItemB
ItemC
Not directly, asSystem::DynamicArray
does not provide concatenation features in C++.不是直接的,因为
System::DynamicArray
在 C++ 中不提供串联功能。 So you would need to create a 3rd TStringDynArray
, size it to the sum of the sizes of the 2 arrays, and individually copy each String
from the 2 arrays into the 3rd array ( String
is reference-counted, so you can't just copy bytes with memcpy()
or equivalent, like you can with arrays of trivial types), eg:因此,您需要创建第 3 个
TStringDynArray
,将其调整为 2 个 arrays 的大小之和,然后将 2 个 arrays 中的每个String
单独复制到第 3 个数组中( String
是引用计数的,因此您不能只复制使用memcpy()
或等效的字节,就像你可以使用普通类型的 arrays 一样),例如:
TStringDynArray Arr1;
// fill Arr1 as needed...
TStringDynArray Arr2;
// fill Arr2 as needed...
TStringDynArray MergedArr;
MergedArr.Length = Arr1.Length + Arr2.Length;
int idx = 0;
for(int i = 0; i < Arr1.Length; ++i) {
MergedArr[idx++] = Arr1[i];
}
for(int i = 0; i < Arr2.Length; ++i) {
MergedArr[idx++] = Arr2[i];
}
// use MergedArr as needed...
Alternatively (C++Builder 10.1 Berlin and later):或者(C++Builder 10.1 Berlin 及更高版本):
#include <algorithm>
TStringDynArray Arr1;
// fill Arr1 as needed...
TStringDynArray Arr2;
// fill Arr2 as needed...
TStringDynArray MergedArr;
MergedArr.Length = Arr1.Length + Arr2.Length;
std::copy(Arr1.begin(), Arr1.end(), MergedArr.begin());
std::copy(Arr2.begin(), Arr2.end(), MergedArr.begin() + Arr1.Length);
// use MergedArr as needed...
In the Clang-based compilers , you can take this a step further by using some variadic template functions to help you concatenate as many input TStringDynArray
arrays as you want, eg:在基于 Clang 的编译器中,您可以更进一步,使用一些可变参数模板函数来帮助您根据需要连接尽可能多的输入
TStringDynArray
arrays,例如:
#include <algorithm>
int ArrLength()
{
return 0;
}
template<typename... Ts>
int ArrLength(TStringDynArray &arr, Ts&... others)
{
return arr.Length + ArrLength(others...);
}
void ArrCopy(TStringDynArray::iterator dst)
{
}
template<typename... Ts>
void ArrCopy(TStringDynArray::iterator dst, TStringDynArray &arr, Ts&... others)
{
std::copy(arr.begin(), arr.end(), dst);
ArrCopy(dst + arr.Length, others...);
}
template<typename... Ts>
TStringDynArray ArrMerge(TStringDynArray &arr, Ts&... others)
{
TStringDynArray res;
res.Length = ArrLength(arr, others...);
ArrCopy(res.begin(), arr, others...);
return res;
}
...
TStringDynArray Arr1;
// fill Arr1 as needed...
TStringDynArray Arr2;
// fill Arr2 as needed...
TStringDynArray MergedArr = ArrMerge(Arr1, Arr2/*, Arr3, Arr4, ...*/);
// use MergedArr as needed...
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