c++ find text in QStringList that starts with "..." using .indexOf - c++

Question

I have a question concerning QStringList:
I have a .txt-File containing several 1000 lines of Data followed by this:
+-------------------------+-------------------+-----------------------|
| Conditions at | X1 | X2 |
+-------------------------+-------------------+-----------------------|
| Time [ms] | 0.10780E-02 | 0.27636E-02 |
| Travel [m] | 0.11366E+00 | 0.18796E+01 |
| Velocity [m/s] | 0.43980E+03 | 0.13920E+04 |
| Acceleration [g] | 0.11543E+06 | 0.20936E+05 |
…
Where the Header (Conditions at…) and the first column (Travel, Time,…) always stay the same but the values vary for each run. From this File I want to read the values (only!) into fields of a GUI.
First I write all data into a QStringList. (Each line of .txt copied to one Element of QStringList)
To get the values, from the QStringList I tried to find the corresponding lines with “.indexOf()" which didn´t work because I have to ask for the exact text of the whole line. Since the values vary, the lines are different for each run and my program is not able to find corresponding lines.
Is there a command like “.indexOf-Starting with certain text” which would find me the lines starting with a certain text for example “| Time [ms]”
Thank you very much
itelly

Answer 1

Yes there is method “.indexOf-Starting with certain text”. You can use regular expressions to match the beggining of a string:
int QStringList::indexOf (const QRegExp& rx, int from = 0) const
Use it in this way:
int timeLineIndex = stringList.indexOf(QRegExp("^\| Time \[ms\].+"));
^ means that this text should be at the beggining of a string
\ escapes special characters
.+ means that any text can follow this
EDIT:
Here is a working example that show how it works:
QStringList stringList;
stringList << "abc 5234 hjd";
stringList << "bnd|gf dfs aaa";
stringList << "das gf dfs aaa";
int index = stringList.indexOf(QRegExp("^bnd\|gf.+"));
qDebug() << index;
Output: 1
EDIT:
Here is a function for ezee usage of this:
int indexOfLineStartingWith(const QStringList& list, const QString& textToFind)
{
return list.indexOf(QRegExp("^" + QRegExp::escape(textToFind) + ".+"));
}
int index = indexOfLineStartingWith(stringList, "bnd|gf"); //it's not needed to escape characters here

Answer 2

First of all your actual data starts from the line 4 (excluding the header). Second - each data string has specific layout, that you can parse. Assuming that you read the whole file into the QStringList, where each item in the list represents each line, you can do the following:
QStringList data;
[..]
for (int i = 3; i < data.size(); i++) {
const QString &line = data.at(i);
// Parse the X1 and X2 columns' values
QString strX1 = line.section('|', 1, 1, QString::SectionSkipEmpty).trimmed();
QString strX2 = line.section('|', 2, 2, QString::SectionSkipEmpty).trimmed();
}