Split QString generated from QGeoCoordinate.

Gourmet

I download coordinates from file created with QGeoCoordinate::toString(QGeoCoordinate::Degrees). It looks like lines with numbers, sometimes without altitude:
-27.46758°, 153.02789°, 28.1m
-27.46758°, 153.02789°
...
I need QStringList with just only string doubles for conversion:

QStringList list = s.split( QRegularExpression(thisHatedRegExpString), QString::SkipEmptyParts );
return QGeoCoordinate( list.at(0).toDouble(), list.at(1).toDouble(), list.size() == 2 ? 0.0 : list.at(2).toDouble() );

To get toDouble() working I need clear string real values without "°" and "m". But how thisHatedRegExpString must look like?... The ", " keeps unneeded parts. I always hated this regular expression syntax.

Christian Ehrlicher

Simply don't use a regex...

QVector<QStringRef> parts = s.splitRef(QLatin1String(", "));
if (parts.size() < 2 || parts.size() > 3)
  return QGeoCoordinate();
if (parts[0].endsWith('°')
  parts[0] = parts[0].chop(1);
if (parts[1].endsWith('°')
  parts[1] = parts[1].chop(1);
if (parts.size() == 3 && parts[2].endsWith('m'))
  parts[2] = parts[2].chop(1);
return QGeoCoordinate(parts.at(0).toDouble(), parts.at(1).toDouble(), parts.size() == 2 ? 0.0 : parts.at(2).toDouble() );

Gourmet

@Christian-Ehrlicher in this case simpler use QStringList and QRegularExpression(", "). The code

QStringList list = s.split( QRegularExpression(", "), QString::SkipEmptyParts );

gives list == {"-27.46758°", "153.02789°", "28.1m"} or {"-27.46758°", "153.02789°"}. No endsWith() checking needed - if line exists it always ends with '°' or 'm'. But I wanted perform all in one split operation.

Christian Ehrlicher

@Gourmet said in Split QString generated from QGeoCoordinate.:

But I wanted perform all in one split operation.

Why? To make it slower? To be someone who wrote a regexp?

Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems.

Gourmet

@Christian-Ehrlicher to make code shorter...

JKSH

@Gourmet said in Split QString generated from QGeoCoordinate.:

to make code shorter...

Readable code is more important than short code.

https://softwareengineering.stackexchange.com/questions/203684/is-fewer-lines-of-code-always-better

Gourmet

@JKSH less to read means easer to read.

Christian Ehrlicher

@Gourmet said in Split QString generated from QGeoCoordinate.:

less to read means easer to read.

So you say me you can read a regexp (which you are not aware to create on your own so I guess you won't understand it later on) is easier to understand than simple string modifications? Nice try...

Gourmet

@Christian-Ehrlicher regexp has one specific feature - it is much more easer to read and understand than to write. This is because of it's "encapsulation" - when you see it you already know what it means. Often it's not needed parse it when reading - just treat as whole thing.

VRonin

I'll go a completely different way

QGeoCoordinate result(0.0,0.0,0.0);
const QRegularExpression dobleMatchingRegExp(QStringLiteral("[-+]?\\d*\\.?\\d+"));
QRegularExpressionMatchIterator i = dobleMatchingRegExp.globalMatch(s);
if(i.hasNext()) result.setLatitude(i.next().capturedRef(0).toDouble());
if(i.hasNext()) result.setLongitude(i.next().capturedRef(0).toDouble());
if(i.hasNext()) result.setAltitude(i.next().capturedRef(0).toDouble());
return result;

Sources:

Gourmet

@VRonin so... cumbersome...