> Sent: Wednesday, September 18, 2019 at 2:50 PM > From: "Giuseppe D'Angelo via Interest" <[email protected]> > To: [email protected] > Subject: Re: [Interest] QByteArray vs QString, arg, why is there no arg()? > > Il 18/09/19 13:16, Jason H ha scritto: > > What's the best way to zero-pad a QByteArray? > > What I want is QByteArray("%1").arg(6, 10, 10, '0') > > Mostly it has to do with the fact that QByteArray is sitting between two > worlds; on one side it's just a container of bytes, on the other side it > has _some_ manipulation functions for ASCII-like strings. "Some" > because, as you've noticed, stuff like the arg() convenience is missing. > > If you really need a QByteArray you can work around this by e.g. using a > printf-like function, what you're looking for is the "%010d" formatting. > > Pseudocode: > > int n = 123; > const char *format = "The number is %010d"; > auto size = qsnprintf(nullptr, 0, format, n); > > QByteArray result(size, Qt::uninitialized); > qsnprintf(result.data(), result.size(), format, n);
That helps, but wasn't the answer I wanted to hear. I have to call qsnprintf() twice. Granted, for valid reasons.and it might be faster than my gluing things together with +. I do prefer python's approach where the character size change does not come with an API change. Maybe discussion for Qt6?. I would think they C++ way would be to have 1 API and a template class? (Though I think some people cringe at that idea) _______________________________________________ Interest mailing list [email protected] https://lists.qt-project.org/listinfo/interest
