C++ 二维向量 push_back
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Two Dimensional Vector push_back
提问by Barry Tormey
I have a two dimensional vector A made up of other vectors B
我有一个由其他向量 B 组成的二维向量 A
vector < vector < int >> A
vector < int > B
I use the push_backfunction to populate B.
我使用该push_back函数来填充 B。
B.push_back(1);
B.push_back(2);
B.push_back(3);
After that vector is populated, I use push_backagain to populate A with B
填充该向量后，我push_back再次使用 B 填充 A
A.push_back(B)
This is done several times so that A eventually results in a vector containing several other vectors looking like:
这样做多次，以便 A 最终产生一个包含其他几个向量的向量，如下所示：
A { {1 , 2 , 3 }, { 2, 2, 2 }, {8, 9, 10} }
How can I make a call to a specific index in A and then continue to add to the vector so that the output would be similar to
如何调用 A 中的特定索引，然后继续添加到向量中，以便输出类似于
A { {1 , 2 , 3 }, { 2, 2, 2, 4, 5, 6 }, {8, 9, 10} }
Something along the lines of
类似的东西
A[2].push_back(4);
A[2].push_back(5);
A[2].push_back(6);
采纳答案by Jesse Good
What you have is correct except that indexes start at 0, so it should be A[1].push_back(4);and not 2.
除了索引从 开始，你所拥有的都是正确的0，所以它应该是A[1].push_back(4);而不是2。
回答by iambeanie
A[2].push_back(4);
A[2].push_back(5);
A[2].push_back(6);
Should work perfectly fine. Except if you want the second element then you'll need to use a[1] as vectors are 0 based.
应该工作得很好。除非您想要第二个元素，否则您需要使用 a[1] 因为向量是基于 0 的。
