QT QMap的增删改查【详】

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QmapOperation.h

#ifndef QMAPOPERATION_H
#define QMAPOPERATION_H

#include <QObject>
#include <QMap>
#include <QDebug>

class QmapOperation : public QObject
{
    Q_OBJECT
public:
    explicit QmapOperation(QObject *parent = nullptr);
    //添加
    void QmapInsert();
    //修改
    void QmapUpdata();
    //查找
    void QmapFind(QString key);
    //遍历
    void QmapTraversal();
    //删除
    void QmapRemove();

public:
    QMap<QString,QString>   m_cQmap;

signals:

public slots:
};

#endif // QMAPOPERATION_H

QmapOperation.cpp

#include "QmapOperation.h"

QmapOperation::QmapOperation(QObject *parent) : QObject(parent)
{

}

void QmapOperation::QmapInsert()
{
    m_cQmap.insert("aaa","leo");
    m_cQmap.insert("bbb","Jason");
    m_cQmap.insert("ccc","May");
    m_cQmap.insert("ddd","Tom");
    m_cQmap.insert("eee","Jack");

    QmapTraversal();
}

void QmapOperation::QmapUpdata()
{
    m_cQmap["bbb"] = "Bob";
    QmapTraversal();
}

void QmapOperation::QmapFind(QString key)
{
    QMap<QString, QString>::iterator i;
    i = m_cQmap.find(key);
    qDebug() << i.key() <<" ==> " << i.value();
}

void QmapOperation::QmapTraversal()
{
    QMap<QString, QString>::const_iterator i;
    for( i=m_cQmap.constBegin(); i!=m_cQmap.constEnd(); ++i)
    {
        qDebug() << i.key() <<" ==> " << i.value();
    }

}

void QmapOperation::QmapRemove()
{
    QMap<QString, QString>::iterator i;
    for( i=m_cQmap.begin(); i!=m_cQmap.end(); ++i)
    {
        if(i.key() == "ccc")
        {
            m_cQmap.erase(i);
            i = m_cQmap.begin()+1;//删除之后要将指针指向后面一个
        }
    }
    QmapTraversal();
}

调用：

    #include "QmapOperation.h"
    
    QmapOperation*  m_pQmapOperation;    
    m_pQmapOperation = new QmapOperation();
    qDebug() << "----insert----";
    m_pQmapOperation->QmapInsert();
    qDebug() << "----updata----";
    m_pQmapOperation->QmapUpdata();
    qDebug() << "----find----";
    m_pQmapOperation->QmapFind("ccc");
    qDebug() << "----remove----";
    m_pQmapOperation->QmapRemove();

输出结果：

----insert----
"aaa"  ==>  "leo"
"bbb"  ==>  "Jason"
"ccc"  ==>  "May"
"ddd"  ==>  "Tom"
"eee"  ==>  "Jack"
----updata----
"aaa"  ==>  "leo"
"bbb"  ==>  "Bob"
"ccc"  ==>  "May"
"ddd"  ==>  "Tom"
"eee"  ==>  "Jack"
----find----
"ccc"  ==>  "May"
----remove----
"aaa"  ==>  "leo"
"bbb"  ==>  "Bob"
"ddd"  ==>  "Tom"
"eee"  ==>  "Jack"