Qt_QString.indesOf和mid测试

#define GID_PREFIX  "dr_"

    QString str = "dr__awedr4";
    int iIdx = str.indexOf(GID_PREFIX);
    qDebug() << iIdx;

    str = "awedr4";
    iIdx = str.indexOf(GID_PREFIX);
    qDebug() << iIdx;

    str = "awedr_4";
    iIdx = str.indexOf(GID_PREFIX);
    qDebug() << iIdx;

0
-1
3

#define GID_PREFIX  "dr_"

    QString str = "dr__awedr4";
    QString str1;

    int iLen_prefix = strlen(GID_PREFIX);
    int iLen_Left = str.length() - iLen_prefix;
    qDebug() << iLen_Left;
    str1 = str.mid(iLen_prefix, iLen_Left);
    qDebug() << str1;
    str1 = str.mid(iLen_prefix);
    qDebug() << str1;

7
"_awedr4"
"_awedr4"