问：STL向量 [英] Q: STL vector
问题描述
嗨
我有一个存储在矢量中的值列表，例如
std :: vector< int> x;
x [0] = 1;
x [1] = 4;
x [2] = 2;
x [3] = 4;
x [4] = 6;
x [5] = 1;
x [6 ] = 4;
任何人都可以提出一种有效的方法来迭代向量，这样
向量只包含唯一值，例如向量中只有一个4的实例出现在
中。也就是说，新的矢量一旦被处理，将是：
{1,4,2,6}
提前致谢
David
Hi
I have a list of values stored in a vector e.g.
std::vector<int> x;
x[0] = 1;
x[1] = 4;
x[2] = 2;
x[3] = 4;
x[4] = 6;
x[5] = 1;
x[6] = 4;
Can anybody suggest an efficient way to iterate through the vector so that
the vector only contains unique values e.g. only one instance of 4 occurs in
the vector. That is, the new vector, once processed, would be:
{1,4,2,6}
Thanks in advance
David
推荐答案
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嗨
我有一个存储在矢量中的值列表，例如
std :: vector< int> x;
x [0] = 1;
x [1] = 4;
x [2] = 2;
x [3] = 4;
x [4] = 6;
x [5] = 1;
x [6] = 4;
任何人都可以提出一种有效的迭代方法向量使得向量只包含唯一值，例如向量中只有一个4的实例出现
。也就是说，新的矢量一旦被处理，将是：
{1,4,2,6}
Hi
I have a list of values stored in a vector e.g.
std::vector<int> x;
x[0] = 1;
x[1] = 4;
x[2] = 2;
x[3] = 4;
x[4] = 6;
x[5] = 1;
x[6] = 4;
Can anybody suggest an efficient way to iterate through the vector so that
the vector only contains unique values e.g. only one instance of 4 occurs in the vector. That is, the new vector, once processed, would be:
{1,4,2,6}
查找标准： ：STL引用中的sort和std :: unique。示例：
std :: sort（x.begin（），x.end（））;
std :: unique（x.begin（） ，x.end（））;
您需要包含< algorithm>首先。
HTH，
Paul
Look up std::sort and std::unique in an STL reference. Example:
std::sort(x.begin(), x.end());
std::unique(x.begin(), x.end());
You''ll need to include <algorithm> first.
HTH,
Paul
非常感谢您的快速回复保罗。非常有用！
为了简化问题，我已经指定了一个整数向量。然而，对于生活中的大部分事情而言，我正在努力解决的真正问题是稍微复杂一些。我所拥有的向量不是整数向量，而是一个向量
的对象，其中有一个成员标识一个名称，即每个对象都有一个
char成员。向量的元素将此成员设置为A，B
等。我想从向量中删除具有相同名称的元素
即例如，只有一个向量将具有名称C。
我猜这是同一类型的问题，因此我的初始帖子，但是一个
稍微复杂一点。
我们非常感谢任何建议。
David
Many thanks for your prompt reply Paul. Very useful!
To simplify the problem I''ve specified a vector of integers. However, as
with most things in life, the true problem I''m trying to solve is a little
bit more complex. The vector I have is not a vector of integers but a vector
of objects which have a member identifying a name i.e. each object has a
char member. The elements of the vector have this member set as "A", "B"
etc. I want to remove elements from the vector which have identical "names"
i.e. only one vector will, for example, have name "C".
I guess that this is the same type of problem, hence my initial post, but a
little more complex.
Any advice will be most appreciated.
David
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嗨
我有一个存储在矢量中的值列表，例如
std :: vector< int> x;
x [0] = 1;
x [1] = 4;
x [2] = 2;
x [3] = 4;
x [4] = 6;
x [5] = 1;
x [6] = 4;
任何人都可以提出一种有效的迭代方法向量所以
，向量只包含唯一值，例如在
Hi
I have a list of values stored in a vector e.g.
std::vector<int> x;
x[0] = 1;
x[1] = 4;
x[2] = 2;
x[3] = 4;
x[4] = 6;
x[5] = 1;
x[6] = 4;
Can anybody suggest an efficient way to iterate through the vector so that the vector only contains unique values e.g. only one instance of 4
向量中只出现一个4
的实例。也就是说，新的向量一旦被处理，将是：
{1,4,2,6}
the vector. That is, the new vector, once processed, would be:
{1,4,2,6}
查找std :: sort和std :: STL参考中的唯一。示例：
std :: sort（x.begin（），x.end（））;
std :: unique（x.begin（），x.end（））;
你需要包含< algorithm>首先。
HTH，
保罗
Look up std::sort and std::unique in an STL reference. Example:
std::sort(x.begin(), x.end());
std::unique(x.begin(), x.end());
You''ll need to include <algorithm> first.
HTH,
Paul
除了当然std :: unique，就像任何其他STL算法一样，实际上不会从向量中删除
。你需要做
ox.erase（std :: unique（ox.begin（），ox.end（）），ox.end（））;
。
john
Except of course std::unique, like any other STL algorithm, will not
actually erase the items from the vector. You need to do
ox.erase(std::unique(ox.begin(), ox.end()), ox.end());
for that.
john
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