Is there a QString
function which takes an int and outputs it as a QString
?
This question is related to
c++
qt
type-conversion
If you need locale-aware number formatting, use QLocale::toString instead.
Moreover to convert whatever you want, you can use QVariant
.
For an int
to a QString
you get:
QVariant(3).toString();
A float
to a string
or a string
to a float
:
QVariant(3.2).toString();
QVariant("5.2").toFloat();
I always use QString::setNum()
.
int i = 10;
double d = 10.75;
QString str;
str.setNum(i);
str.setNum(d);
setNum()
is overloaded in many ways. See QString
class reference.
In it's simplest form, use the answer of Georg Fritzsche
For a bit advanced, you can use this,
QString QString::arg ( int a, int fieldWidth = 0, int base = 10, const QChar & fillChar = QLatin1Char( ' ' ) ) const
Get the documentation and an example here..
And if you want to put it into string within some text context, forget about +
operator.
Simply do:
// Qt 5 + C++11
auto i = 13;
auto printable = QStringLiteral("My magic number is %1. That's all!").arg(i);
// Qt 5
int i = 13;
QString printable = QStringLiteral("My magic number is %1. That's all!").arg(i);
// Qt 4
int i = 13;
QString printable = QString::fromLatin1("My magic number is %1. That's all!").arg(i);
Yet another option is to use QTextStream and the <<
operator in much the same way as you would use cout
in C++:
QPoint point(5,1);
QString str;
QTextStream(&str) << "Mouse click: (" << point.x() << ", " << point.y() << ").";
// OUTPUT:
// Mouse click: (5, 1).
Because operator <<()
has been overloaded, you can use it for multiple types, not just int
. QString::arg()
is overloaded, for example arg(int a1, int a2)
, but there is no arg(int a1, QString a2)
, so using QTextStream()
and operator <<
is convenient when formatting longer strings with mixed types.
Caution: You might be tempted to use the sprintf()
facility to mimic C style printf()
statements, but it is recommended to use QTextStream
or arg()
because they support Unicode string
s.
Just for completeness, you can use the standard library and do QString qstr = QString::fromStdString(std::to_string(42));
Source: Stackoverflow.com