[Qt-interest] working with qfile

[Bob Hood]

On 9/26/2011 7:14 AM, Sahana Bhaskar wrote:
>
>  
>
> Hi all,
>
>  
>
> I am trying to read a text file using the qfiles. I need to see if the file
> contains a specific string and if it does I need to replace the whole line
> with a new line. I tried using QTextStream. Could anyone please help me out
> with this?
>

Simple enough (not tested, but should give you the idea):

    QRegExp text_to_find("^Hello world!$");

    QFile out_file(out_file_name);
    if(!out_file.open(QIODevice::WriteOnly | QIODevice::Text))
        // deal with this error
        return;

    QFile in_file(in_file_name);
    if(!in_file.open(QIODevice::ReadOnly | QIODevice::Text))
        // deal with this error
        return;

    in_text = in_file.readAll();

    QTextStream text_out(&out_file);

    QList<QByteArray> lines = in_text.split('\n');
    foreach(QByteArray line, lines)
    {
        if(text_to_find.indexIn(line, 0) != -1)
            // this line contains the text to be replaced
            text_out << "Goodbye world!\n";
        else
            text_out << line
    }

    in_file.close();
    out_file.close();

Render me gone,                       |||
Bob                                 ^(===)^
---------------------------------oOO--(_)--OOo---------------------------------
   "One of the penalties for refusing to participate in politics is that you
           end up being governed by your inferiors." -- /Plato/

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