Attributeerror: 'Qstring' Object has no attribute 'strip'

Question

I’m making a small application in Pyqt4 to understand how it works. In a certain part, I’m using a callback function to display in a QLabel the text that is typed in QtextEdit.

This text should be trimmed (remove spaces before and after the string).

When I tried to use the function strip present in str Python the following error occurred:

Attributeerror: 'Qstring' Object has no attribute 'strip'

From what I understand, in Pyqt, the string is not an object str and yes QString and QString does not have the method strip.

In that case, what can I do to get my string handled?

Code:

def onButtonOkClicked(self):

    def setText():
        text = self.line.toPlainText().strip();
        self.label.setText(text)

    QtCore.QObject.connect(self.buttonOk, QtCore.SIGNAL("clicked()"), setText)

Answer 1

I’m just answering to explain something:

The strip (str.strip) is a method for Python strings, which is also supported by bytes (bytes.strip([chars]) and bytearray.strip([chars]))

Already the QString is different from str, resume it is a Qt object and will not have access to the same methods used in Python native strings.

You will have to use the methods of own QString as documented http://doc.qt.io/qt-5/qstring.html#public-functions

In the case as cited in the other answers, use the trimmed:

self.line.toPlainText().trimmed();

It is worth noting that there is no equivalent to ltrim(), rtrim() or pass arguments to change what type of character you want to trim, as occurs in strip([chars])

print("---foobar----".strip('-'))

that would result in foobar, then if you want certain operations that exist in str() use only str and then convert to QString (when necessary).

Answer 2

Can use simplified() of own QString. It is a more limited method, but it can work. Depending on what you want can be used to trimmed() also.

Can use replace(QString(" "), QString("")) if you want other characters.

Although I suggest avoiding, can also convert to the string python:

str(text)

The two encodings are completely different, so if you keep converting from one to the other every time you waste resources. When using Qt the idea is to get as much as possible with it and only convert when it is strictly necessary.

Answer 3

The class QString has the function trimmed(), that returns a new QString with whitespace removed from the beginning and end of text.

Documentation of the Pyhton version: http://pyqt.sourceforge.net/Docs/PyQt4/qstring.html#trimmed

Documentation of version C++: http://doc.qt.io/qt-4.8/qstring.html#trimmed