examples: clean and improve code

- removing '\' from long lines,
- use f-strings instead of concatenating strings
- Use f-strings instead of the old '%' formatting

Task-number: PYSIDE-841
Change-Id: I4983c25a6272e10119d5d1a74c180828ca6f64e6
Reviewed-by: Christian Tismer <tismer@stackless.com>

21 files changed, 73 insertions, 70 deletions

diff --git a/examples/axcontainer/axviewer/axviewer.py b/examples/axcontainer/axviewer/axviewer.py
index fd4972a34..e7e03d2c9 100644
--- a/examples/axcontainer/axviewer/axviewer.py
+++ b/examples/axcontainer/axviewer/axviewer.py
@@ -73,7 +73,7 @@ class MainWindow(QMainWindow):
         if axSelect.exec() == QDialog.Accepted:
             clsid = axSelect.clsid()
             if not self.axWidget.setControl(clsid):
-                QMessageBox.warning(self, "AxViewer", "Unable to load " + clsid + ".")
+                QMessageBox.warning(self, "AxViewer", f"Unable to load {clsid}.")
 
 
 if __name__ == '__main__':
diff --git a/examples/corelib/threads/mandelbrot.py b/examples/corelib/threads/mandelbrot.py
index 2e45afadc..c95966119 100644
--- a/examples/corelib/threads/mandelbrot.py
+++ b/examples/corelib/threads/mandelbrot.py
@@ -67,8 +67,8 @@ NUM_PASSES = 8
 INFO_KEY = 'info'
 
 
-HELP = "Use mouse wheel or the '+' and '-' keys to zoom. Press and " \
-       "hold left mouse button to scroll."
+HELP = ("Use mouse wheel or the '+' and '-' keys to zoom. Press and "
+       "hold left mouse button to scroll.")
 
 
 class RenderThread(QThread):
diff --git a/examples/multimedia/audiooutput/audiooutput.py b/examples/multimedia/audiooutput/audiooutput.py
index 322603c2b..0e9a2c10a 100644
--- a/examples/multimedia/audiooutput/audiooutput.py
+++ b/examples/multimedia/audiooutput/audiooutput.py
@@ -69,40 +69,40 @@ class Generator(QIODevice):
         self.m_pos = 0
         self.close()
 
-    def generateData(self, format, durationUs, sampleRate):
+    def generateData(self, fmt, durationUs, sampleRate):
         pack_format = ''
 
-        if format.sampleSize() == 8:
-            if format.sampleType() == QAudioFormat.UnSignedInt:
+        if fmt.sampleSize() == 8:
+            if fmt.sampleType() == QAudioFormat.UnSignedInt:
                 scaler = lambda x: ((1.0 + x) / 2 * 255)
                 pack_format = 'B'
-            elif format.sampleType() == QAudioFormat.SignedInt:
+            elif fmt.sampleType() == QAudioFormat.SignedInt:
                 scaler = lambda x: x * 127
                 pack_format = 'b'
-        elif format.sampleSize() == 16:
-            if format.sampleType() == QAudioFormat.UnSignedInt:
+        elif fmt.sampleSize() == 16:
+            if fmt.sampleType() == QAudioFormat.UnSignedInt:
                 scaler = lambda x: (1.0 + x) / 2 * 65535
-                pack_format = '<H' if format.byteOrder() == QAudioFormat.LittleEndian else '>H'
-            elif format.sampleType() == QAudioFormat.SignedInt:
+                pack_format = '<H' if fmt.byteOrder() == QAudioFormat.LittleEndian else '>H'
+            elif fmt.sampleType() == QAudioFormat.SignedInt:
                 scaler = lambda x: x * 32767
-                pack_format = '<h' if format.byteOrder() == QAudioFormat.LittleEndian else '>h'
+                pack_format = '<h' if fmt.byteOrder() == QAudioFormat.LittleEndian else '>h'
 
         assert(pack_format != '')
 
-        channelBytes = format.sampleSize() // 8
-        sampleBytes = format.channelCount() * channelBytes
+        channelBytes = fmt.sampleSize() // 8
+        sampleBytes = fmt.channelCount() * channelBytes
 
-        length = (format.sampleRate() * format.channelCount() * (format.sampleSize() // 8)) * durationUs // 100000
+        length = (fmt.sampleRate() * fmt.channelCount() * (fmt.sampleSize() // 8)) * durationUs // 100000
 
         self.m_buffer.clear()
         sampleIndex = 0
-        factor = 2 * pi * sampleRate / format.sampleRate()
+        factor = 2 * pi * sampleRate / fmt.sampleRate()
 
         while length != 0:
-            x = sin((sampleIndex % format.sampleRate()) * factor)
+            x = sin((sampleIndex % fmt.sampleRate()) * factor)
             packed = pack(pack_format, int(scaler(x)))
 
-            for _ in range(format.channelCount()):
+            for _ in range(fmt.channelCount()):
                 self.m_buffer.append(packed)
                 length -= channelBytes
 
@@ -230,10 +230,12 @@ class AudioTest(QMainWindow):
             self.m_audioOutput.setVolume(value / 100.0)
 
     def notified(self):
-        qWarning("bytesFree = %d, elapsedUSecs = %d, processedUSecs = %d" % (
-                self.m_audioOutput.bytesFree(),
-                self.m_audioOutput.elapsedUSecs(),
-                self.m_audioOutput.processedUSecs()))
+        bytes_free = self.m_audioOutput.bytesFree()
+        elapsed = self.m_audioOutput.elapsedUSecs()
+        processed = self.m_audioOutput.processedUSecs()
+        qWarning(f"bytesFree = {bytes_free}, "
+                 f"elapsedUSecs = {elapsed}, "
+                 f"processedUSecs = {processed}")
 
     def pullTimerExpired(self):
         if self.m_audioOutput is not None and self.m_audioOutput.state() != QAudio.StoppedState:
@@ -284,7 +286,8 @@ class AudioTest(QMainWindow):
         QAudio.IdleState: "IdleState"}
 
     def handleStateChanged(self, state):
-        qWarning("state = " + self.stateMap.get(state, "Unknown"))
+        state = self.stateMap.get(state, 'Unknown')
+        qWarning(f"state = {state}")
 
 
 if __name__ == '__main__':
diff --git a/examples/multimedia/camera/camera.py b/examples/multimedia/camera/camera.py
index e7e12cbe7..8ec3c869d 100644
--- a/examples/multimedia/camera/camera.py
+++ b/examples/multimedia/camera/camera.py
@@ -127,8 +127,8 @@ class MainWindow(QMainWindow):
 
         if self.camera.status() != QCamera.UnavailableStatus:
             name = self.cameraInfo.description()
-            self.setWindowTitle("PySide6 Camera Example (" + name + ")")
-            self.statusBar().showMessage("Starting: '" + name + "'", 5000)
+            self.setWindowTitle(f"PySide6 Camera Example ({name})")
+            self.statusBar().showMessage(f"Starting: '{name}'", 5000)
             self.camera.start()
         else:
             self.setWindowTitle("PySide6 Camera Example")
@@ -138,7 +138,7 @@ class MainWindow(QMainWindow):
     def nextImageFileName(self):
         picturesLocation = QStandardPaths.writableLocation(QStandardPaths.PicturesLocation)
         dateString = QDate.currentDate().toString("yyyyMMdd")
-        pattern = picturesLocation + "/pyside6_camera_" + dateString + "_{:03d}.jpg"
+        pattern = f"{picturesLocation}/pyside6_camera_{dateString}_{:03d}.jpg"
         n = 1
         while True:
             result = pattern.format(n)
diff --git a/examples/opengl/textures/textures.py b/examples/opengl/textures/textures.py
index 521c099b3..cbefe41d6 100644
--- a/examples/opengl/textures/textures.py
+++ b/examples/opengl/textures/textures.py
@@ -110,7 +110,7 @@ class GLWidget(QtOpenGL.QGLWidget):
         if not GLWidget.sharedObject:
             self.textures = []
             for i in range(6):
-                self.textures.append(self.bindTexture(QtGui.QPixmap(":/images/side%d.png" % (i + 1))))
+                self.textures.append(self.bindTexture(QtGui.QPixmap(f":/images/side{i + 1}.png")))
             GLWidget.sharedObject = self.makeObject()
         GLWidget.refCount += 1
 
diff --git a/examples/samplebinding/main.py b/examples/samplebinding/main.py
index f6f9f1fa9..bc5e16eec 100644
--- a/examples/samplebinding/main.py
+++ b/examples/samplebinding/main.py
@@ -64,7 +64,7 @@ class VanillaChocolateCherryIcecream(VanillaChocolateIcecream):
 
     def getFlavor(self):
         base_flavor = super(VanillaChocolateCherryIcecream, self).getFlavor()
-        return base_flavor + " and a cherry"
+        return f"{base_flavor} and a cherry"
 
 
 if __name__ == '__main__':
diff --git a/examples/sql/books/bookwindow.py b/examples/sql/books/bookwindow.py
index 0b6cc5f44..c57db4afb 100644
--- a/examples/sql/books/bookwindow.py
+++ b/examples/sql/books/bookwindow.py
@@ -114,7 +114,7 @@ class BookWindow(QMainWindow, Ui_BookWindow):
 
     def showError(err):
         QMessageBox.critical(self, "Unable to initialize Database",
-                    "Error initializing database: " + err.text())
+                    f"Error initializing database: {err.text()}")
 
     def create_menubar(self):
         file_menu = self.menuBar().addMenu(self.tr("&File"))
diff --git a/examples/webchannel/standalone/main.py b/examples/webchannel/standalone/main.py
index f61954fc5..68f199336 100644
--- a/examples/webchannel/standalone/main.py
+++ b/examples/webchannel/standalone/main.py
@@ -61,7 +61,7 @@ if __name__ == '__main__':
         print('The example requires SSL support.')
         sys.exit(-1)
     cur_dir = os.path.dirname(os.path.abspath(__file__))
-    jsFileInfo = QFileInfo(cur_dir + "/qwebchannel.js")
+    jsFileInfo = QFileInfo(f"{cur_dir}/qwebchannel.js")
     if not jsFileInfo.exists():
         QFile.copy(":/qtwebchannel/qwebchannel.js",
                    jsFileInfo.absoluteFilePath())
@@ -88,7 +88,7 @@ if __name__ == '__main__':
     channel.registerObject("core", core)
 
     # open a browser window with the client HTML page
-    url = QUrl.fromLocalFile(cur_dir + "/index.html")
+    url = QUrl.fromLocalFile(f"{cur_dir}/index.html")
     QDesktopServices.openUrl(url)
 
     message = f"Initialization complete, opening browser at {url.toDisplayString()}."
diff --git a/examples/widgets/animation/easing/easing.py b/examples/widgets/animation/easing/easing.py
index 24d37bd55..ba7f2d363 100644
--- a/examples/widgets/animation/easing/easing.py
+++ b/examples/widgets/animation/easing/easing.py
@@ -166,10 +166,10 @@ class Window(QWidget):
         # different curve types.  We do the Python equivalant (but without
         # cheating)
         curve_types = [(n, c) for n, c in QEasingCurve.__dict__.items()
-                        if isinstance(c, QEasingCurve.Type) \
-                            and c != QEasingCurve.Custom    \
-                            and c != QEasingCurve.NCurveTypes \
-                            and c != QEasingCurve.TCBSpline]
+                        if (isinstance(c, QEasingCurve.Type)
+                            and c != QEasingCurve.Custom
+                            and c != QEasingCurve.NCurveTypes
+                            and c != QEasingCurve.TCBSpline)]
         curve_types.sort(key=lambda ct: ct[1])
 
         painter.begin(pix)
diff --git a/examples/widgets/dialogs/classwizard/classwizard.py b/examples/widgets/dialogs/classwizard/classwizard.py
index 1daf91bbf..a7c7e2c58 100644
--- a/examples/widgets/dialogs/classwizard/classwizard.py
+++ b/examples/widgets/dialogs/classwizard/classwizard.py
@@ -65,9 +65,9 @@ BASE_CLASSES = ['<None>', 'PySide6.QtCore.QObject',
 PYTHON_TYPES = ['int', 'list', 'str']
 
 
-INTRODUCTION = """This wizard will generate a skeleton Python class definition,\
- including a few functions. You simply need to specify the class name and set\
- a few options to produce a Python file."""
+INTRODUCTION = ("This wizard will generate a skeleton Python class definition, "
+                "including a few functions. You simply need to specify the class name and set "
+                "a few options to produce a Python file.")
 
 
 def property_accessors(property_type, name):
@@ -361,14 +361,14 @@ class OutputFilesPage(QWizardPage):
         self._file_line_edit.setText(class_name.lower() + '.py')
         self.set_output_dir(QDir.tempPath())
 
-    def set_output_dir(self, dir):
-        self._output_dir_line_edit.setText(QDir.toNativeSeparators(dir))
+    def set_output_dir(self, directory):
+        self._output_dir_line_edit.setText(QDir.toNativeSeparators(directory))
 
     def output_dir(self):
         return QDir.fromNativeSeparators(self._output_dir_line_edit.text())
 
     def file_name(self):
-        return self.output_dir() + '/' + self._file_line_edit.text()
+        return f"{self.output_dir()}/{self._file_line_edit.text()}"
 
     def _choose_output_dir(self):
         directory = QFileDialog.getExistingDirectory(self, "Output Directory",
diff --git a/examples/widgets/dialogs/standarddialogs/standarddialogs.py b/examples/widgets/dialogs/standarddialogs/standarddialogs.py
index 86397adc2..fb2dbc184 100644
--- a/examples/widgets/dialogs/standarddialogs/standarddialogs.py
+++ b/examples/widgets/dialogs/standarddialogs/standarddialogs.py
@@ -75,10 +75,10 @@ class DialogOptionsWidget(QGroupBox):
 
 
 class Dialog(QDialog):
-    MESSAGE = "<p>Message boxes have a caption, a text, and up to three " \
-            "buttons, each with standard or custom texts.</p>" \
-            "<p>Click a button to close the message box. Pressing the Esc " \
-            "button will activate the detected escape button (if any).</p>"
+    MESSAGE = ("<p>Message boxes have a caption, a text, and up to three "
+               "buttons, each with standard or custom texts.</p>"
+               "<p>Click a button to close the message box. Pressing the Esc "
+               "button will activate the detected escape button (if any).</p>")
 
     def __init__(self, parent=None):
         super().__init__(parent)
@@ -285,7 +285,7 @@ class Dialog(QDialog):
         d, ok = QInputDialog.getDouble(self, "QInputDialog.getDouble()",
                 "Amount:", 37.56, -10000, 10000, 2)
         if ok:
-            self._double_label.setText("$%g" % d)
+            self._double_label.setText(f"${d:g}")
 
     def set_item(self):
         items = ("Spring", "Summer", "Fall", "Winter")
diff --git a/examples/widgets/gallery/widgetgallery.py b/examples/widgets/gallery/widgetgallery.py
index 0693750ac..bd7f8ce6b 100644
--- a/examples/widgets/gallery/widgetgallery.py
+++ b/examples/widgets/gallery/widgetgallery.py
@@ -305,7 +305,7 @@ class WidgetGallery(QDialog):
         # Create centered/italic HTML rich text
         rich_text = "<html><head/><body><i>"
         for line in POEM.split('\n'):
-            rich_text += "<center>" + line + "</center>"
+            rich_text += f"<center>{line}</center>"
         rich_text += "</i></body></html>"
 
         text_edit = QTextEdit(rich_text)
diff --git a/examples/widgets/graphicsview/diagramscene/diagramscene.py b/examples/widgets/graphicsview/diagramscene/diagramscene.py
index 7588c50a0..b068a8253 100644
--- a/examples/widgets/graphicsview/diagramscene/diagramscene.py
+++ b/examples/widgets/graphicsview/diagramscene/diagramscene.py
@@ -367,10 +367,10 @@ class DiagramScene(QGraphicsScene):
             self.removeItem(self.line)
             self.line = None
 
-            if len(start_items) and len(end_items) and \
-                    isinstance(start_items[0], DiagramItem) and \
-                    isinstance(end_items[0], DiagramItem) and \
-                    start_items[0] != end_items[0]:
+            if (len(start_items) and len(end_items) and
+                    isinstance(start_items[0], DiagramItem) and
+                    isinstance(end_items[0], DiagramItem) and
+                    start_items[0] != end_items[0]):
                 start_item = start_items[0]
                 end_item = end_items[0]
                 arrow = Arrow(start_item, end_item)
diff --git a/examples/widgets/graphicsview/dragdroprobot/dragdroprobot.py b/examples/widgets/graphicsview/dragdroprobot/dragdroprobot.py
index 8732c1c67..4f074aa19 100644
--- a/examples/widgets/graphicsview/dragdroprobot/dragdroprobot.py
+++ b/examples/widgets/graphicsview/dragdroprobot/dragdroprobot.py
@@ -142,8 +142,8 @@ class RobotPart(QGraphicsItem):
         self.setAcceptDrops(True)
 
     def dragEnterEvent(self, event):
-        if event.mimeData().hasColor() or \
-          (isinstance(self, RobotHead) and event.mimeData().hasImage()):
+        if (event.mimeData().hasColor() or
+                (isinstance(self, RobotHead) and event.mimeData().hasImage())):
             event.setAccepted(True)
             self._drag_over = True
             self.update()
diff --git a/examples/widgets/itemviews/addressbook/adddialogwidget.py b/examples/widgets/itemviews/addressbook/adddialogwidget.py
index eb848c4d6..1462711a8 100644
--- a/examples/widgets/itemviews/addressbook/adddialogwidget.py
+++ b/examples/widgets/itemviews/addressbook/adddialogwidget.py
@@ -99,5 +99,5 @@ if __name__ == "__main__":
     if (dialog.exec()):
         name = dialog.name
         address = dialog.address
-        print("Name:" + name)
-        print("Address:" + address)
+        print(f"Name: {name}")
+        print(f"Address: {address}")
diff --git a/examples/widgets/itemviews/addressbook/newaddresstab.py b/examples/widgets/itemviews/addressbook/newaddresstab.py
index 63ccbcc30..407c48aec 100644
--- a/examples/widgets/itemviews/addressbook/newaddresstab.py
+++ b/examples/widgets/itemviews/addressbook/newaddresstab.py
@@ -81,8 +81,8 @@ class NewAddressTab(QWidget):
 if __name__ == "__main__":
 
     def print_address(name, address):
-        print("Name:" + name)
-        print("Address:" + address)
+        print(f"Name: {name}")
+        print(f"Address: {address}")
 
     import sys
     from PySide6.QtWidgets import QApplication
diff --git a/examples/widgets/itemviews/jsonmodel/jsonmodel.py b/examples/widgets/itemviews/jsonmodel/jsonmodel.py
index 5fa324a03..432bc4b33 100644
--- a/examples/widgets/itemviews/jsonmodel/jsonmodel.py
+++ b/examples/widgets/itemviews/jsonmodel/jsonmodel.py
@@ -170,7 +170,7 @@ class JsonModel(QAbstractItemModel):
 
         assert isinstance(
             document, (dict, list, tuple)
-        ), "`document` must be of dict, list or tuple, " "not %s" % type(document)
+        ), "`document` must be of dict, list or tuple, " f"not {type(document)}"
 
         self.beginResetModel()
 
diff --git a/examples/widgets/layouts/dynamiclayouts/dynamiclayouts.py b/examples/widgets/layouts/dynamiclayouts/dynamiclayouts.py
index 994a6fb45..c0e3266ce 100644
--- a/examples/widgets/layouts/dynamiclayouts/dynamiclayouts.py
+++ b/examples/widgets/layouts/dynamiclayouts/dynamiclayouts.py
@@ -124,8 +124,8 @@ class Dialog(QDialog):
         self._rotable_widgets.append(QProgressBar())
         count = len(self._rotable_widgets)
         for i in range(count):
-            self._rotable_widgets[i].valueChanged[int].\
-                connect(self._rotable_widgets[(i + 1) % count].setValue)
+            element = self._rotable_widgets[(i + 1) % count]
+            self._rotable_widgets[i].valueChanged[int].connect(element.setValue)
 
         self._rotable_layout = QGridLayout()
         self._rotable_group_box.setLayout(self._rotable_layout)
diff --git a/examples/widgets/mainwindows/mdi/mdi.py b/examples/widgets/mainwindows/mdi/mdi.py
index 29ee71204..c674ab783 100644
--- a/examples/widgets/mainwindows/mdi/mdi.py
+++ b/examples/widgets/mainwindows/mdi/mdi.py
@@ -68,7 +68,7 @@ class MdiChild(QTextEdit):
         self._is_untitled = True
         self._cur_file = f"document{MdiChild.sequence_number}.txt"
         MdiChild.sequence_number += 1
-        self.setWindowTitle(self._cur_file + '[*]')
+        self.setWindowTitle(f"{self._cur_file}[*]")
 
         self.document().contentsChanged.connect(self.document_was_modified)
 
@@ -161,7 +161,7 @@ class MdiChild(QTextEdit):
         self._is_untitled = False
         self.document().setModified(False)
         self.setWindowModified(False)
-        self.setWindowTitle(self.user_friendly_current_file() + "[*]")
+        self.setWindowTitle(f"{self.user_friendly_current_file()}[*]")
 
     def stripped_name(self, fullFileName):
         return QFileInfo(fullFileName).fileName()
diff --git a/examples/widgets/painting/basicdrawing/basicdrawing.py b/examples/widgets/painting/basicdrawing/basicdrawing.py
index 941fe4256..d7849b0cc 100644
--- a/examples/widgets/painting/basicdrawing/basicdrawing.py
+++ b/examples/widgets/painting/basicdrawing/basicdrawing.py
@@ -59,8 +59,8 @@ class RenderArea(QWidget):
         QPoint(90, 70)
     ])
 
-    Line, Points, Polyline, Polygon, Rect, RoundedRect, Ellipse, Arc, Chord, \
-            Pie, Path, Text, Pixmap = range(13)
+    (Line, Points, Polyline, Polygon, Rect, RoundedRect, Ellipse,
+     Arc, Chord, Pie, Path, Text, Pixmap) = range(13)
 
     def __init__(self, parent=None):
         super().__init__(parent)
diff --git a/examples/widgets/state-machine/rogue/rogue.py b/examples/widgets/state-machine/rogue/rogue.py
index acf213ae6..1234bea0b 100644
--- a/examples/widgets/state-machine/rogue/rogue.py
+++ b/examples/widgets/state-machine/rogue/rogue.py
@@ -53,11 +53,11 @@ class MovementTransition(QEventTransition):
         self.window = window
 
     def eventTest(self, event):
-        if event.type() == QEvent.StateMachineWrapped and \
-          event.event().type() == QEvent.KeyPress:
+        if (event.type() == QEvent.StateMachineWrapped and
+                event.event().type() == QEvent.KeyPress):
             key = event.event().key()
-            return key == Qt.Key_2 or key == Qt.Key_8 or \
-                key == Qt.Key_6 or key == Qt.Key_4
+            return (key == Qt.Key_2 or key == Qt.Key_8 or
+                    key == Qt.Key_6 or key == Qt.Key_4)
         return False
 
     def onTransition(self, event):
@@ -109,8 +109,8 @@ class MainWindow(QMainWindow):
         for x in range(self.width):
             column = []
             for y in range(self.height):
-                if x == 0 or x == self.width - 1 or y == 0 or \
-                  y == self.height - 1 or generator.bounded(0, 40) == 0:
+                if (x == 0 or x == self.width - 1 or y == 0 or
+                        y == self.height - 1 or generator.bounded(0, 40) == 0):
                     column.append('#')
                 else:
                     column.append('.')