std::unique and removing duplicates from a container of objects-优快云博客

本文介绍了一种使用C++标准库函数unique结合自定义比较器去除Packet对象重复的方法，通过两种方式实现：一是修改Packet类以支持对象比较；二是提供外部比较函数用于比较指向Packet对象的指针。

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class Packet
{
public:
Packet(string fTime, string rID) : filingTime(fTime), recordID(rID)

  string getFilingTime() {return filingTime;}
  string getRecordId() {return recordID;}

private:
  string filingTime;
  string recordID;

};

Two options to be able to use std::unique:

Define an operator== method for Packet and change the vector<Packet*> to vector<Packet>.

bool Packet::operator==(const Packet& rhs) const
{
    if (getFilingTime() != rhs.getFilingTime())
        return false;
    if (getSpid() != rhs.getSpid())
        return false;
    return true;
}

//etc.

int main()
{
    vector<Packet> pkts;
    pkts.push_back(Packet("10:20", "1004"));
    pkts.push_back(Packet("10:20", "1004")); // not unique (duplicate of the line above)
    pkts.push_back(Packet("10:20", "251"));
    pkts.push_back(Packet("10:20", "1006"));

    // remove packet from vector if time and ID are the same

     pkts.erase(unique(pkts.begin(), pkts.end()), pkts.end());                   

    return 0;
}

Keep the vector as vector<Packet*> and define a method to compare the elements.

bool comparePacketPtrs(Packet* lhs, Packet* rhs)
{
    if (lhs->getFilingTime() != rhs->getFilingTime())
        return false;
    if (lhs->getSpid() != rhs->getSpid())
        return false;
    return true;
}

//etc.

int main()
{
    vector<Packet*> pkts;
    pkts.push_back(new Packet("10:20", "1004"));
    pkts.push_back(new Packet("10:20", "1004")); // not unique (duplicate of the line above)
    pkts.push_back(new Packet("10:20", "251"));
    pkts.push_back(new Packet("10:20", "1006"));

    // remove packet from vector if time and ID are the same

     pkts.erase(unique(pkts.begin(), pkts.end(), comparePacketPtrs), pkts.end());                   

    return 0;
}

转载于:https://my.oschina.net/wdyoschina/blog/1502999