How to convert QList<QByteArray> to QStringList ?

sonichy

How to convert QList<QByteArray> to QStringList ?
I want to use QStringList::filter() function.

Paul Colby

How to convert QList<QByteArray> to QStringList ?

It depends on what character encoding is used in the QByteArrays, but assuming they use the local system's 8-bit encoding (for example), you can do it like:

QStringList toStringList(const QList<QByteArray> list) {
    QStringList strings;
    foreach (const QByteArray &item, list) {
        strings.append(QString::fromLocal8Bit(item)); // Assuming local 8-bit.
    }
    return strings;
}

Of course, you can replace the QString::fromLocal8Bit() with whatever makes sense for your encoding.

I want to use QStringList::filter() function.

The above will work. But if you're only interested in the QStringList::filter() overload that takes a QString pattern, and you want to be case sesnsitive (the default), then you can avoid the string conversions by rolling your own "filtered" function like:

QList<QByteArray> filtered(const QList<QByteArray> list, const QByteArray &bytes) {
    QList<QByteArray> result;
    foreach (const QByteArray &item, list) {
        if (item.contains(bytes))
            result.append(item);
    }
    return result;
}

An example of using both the above functions:

    const QList<QByteArray> list = { "a", "b", "c", "abc", "123", "123abc" };
    const QStringList strings = toStringList(list);

    qDebug() << "list:            " << list;
    qDebug() << "strings:         " << strings;
    qDebug() << "strings-filtered:" << strings.filter(QLatin1String("b"));
    qDebug() << "list-filtered:   " << filtered(list, "b");

Outputs:

list:             ("a", "b", "c", "abc", "123", "123abc")
strings:          ("a", "b", "c", "abc", "123", "123abc")
strings-filtered: ("b", "abc", "123abc")
list-filtered:    ("b", "abc", "123abc")

Cheers.