How to create QString in PyQt4?

>>> from PyQt4 import QtCore
>>> str = QtCore.QString('Hello')
AttributeError: 'module' object has no attribute 'QString'

>>> QtCore.QString._init_(self)
AttributeError: 'module' object has no attribute 'QString' 

Yes, I've read QString Class Reference

Why can't I import QString from QtCore, as specified in the docs ?


In [1]: from PyQt4 import QtCore
In [2]: s = QtCore.QString('foo')
In [3]: s
Out[3]: PyQt4.QtCore.QString(u'foo')

In Python 3, QString is automatically mapped to the native Python string by default:

The QString class is implemented as a mapped type that is automatically converted to and from a Python string. In addition a None is converted to a null QString. However, a null QString is converted to an empty Python string (and not None). (This is because Qt often returns a null QString when it should probably return an empty QString.)

The QChar and QStringRef classes are implemented as mapped types that are automatically converted to and from Python strings.

The QStringList class is implemented as a mapped type that is automatically converted to and from Python lists of strings.

The QLatin1Char, QLatin1String and QStringMatcher classes are not implemented.

From PyQt4 4.6+ in Python3 QString doesn't exist and you are supposed to use ordinary Python3 unicode objects (string literals). To do this so that your code will work in both Python 2.x AND Python 3.x you can do following:

    from PyQt4.QtCore import QString
except ImportError:
    # we are using Python3 so QString is not defined
    QString = type("")

Depending on your use case you might get away with this simple hack.

It depends on your import statement.

If you write

from PyQt4 import QtGui, QtCore

you must call QString with

yourstr = QtCore.QString('foo')

I think you've written this :

from PyQt4.QtGui import *
from PyQt4.QtCore import *

It's not really recommended, but you should call String with :

yourstr = QString('foo')

Need Your Help

Refactoring from ActiveRecord to DataMapper

design-patterns activerecord refactoring datamapper

Have you refactored from an ActiveRecord to a DataMapper pattern? What conditions prompted the switch? I'm primarily interested in web based applications, but would like to know the challenges that

How should I change my Graph structure (very slow insertion)?

c graph hashtable time-complexity space-complexity

This program I'm doing is about a social network, which means there are users and their profiles. The profiles structure is UserProfile.