How to use the pyqtgraph.PlotWidget function in pyqtgraph

numpyMatrix = df.as_matrix()

newdf = pd.concat([df.SiO2 ,df.Ratio, df.CaO], axis=1)

X= newdf.as_matrix()



## Define a top-level widget to hold everything
w = QtGui.QWidget()

## Create some widgets to be placed inside
btn = QtGui.QPushButton('press me')
text = QtGui.QLineEdit('enter text')
listw = QtGui.QListWidget()
view = pg.PlotWidget()
view.addLegend()

view.plot(X[:, 0], X[:,2], pen=None, symbol='o', symbolPen=None, symbolSize=10, symbolBrush=(100, 255, 255, 88), name=y[0])

## Create a grid layout to manage the widgets size and position
layout = QtGui.QGridLayout()
w.setLayout(layout)

## Add widgets to the layout in their proper positions
layout.addWidget(btn, 0, 0)   # button goes in upper-left
layout.addWidget(text, 1, 0)   # text edit goes in middle-left
layout.addWidget(listw, 2, 0)  # list widget goes in bottom-left
layout.addWidget(view, 0, 1, 3, 1)  # plot goes on right side, spanning 3 rows

## Display the widget as a new window
w.show()

font.setWeight(75)
        self.label_4.setFont(font)
        self.label_4.setObjectName("label_4")
        self.horizontalLayout_2.addWidget(self.label_4)
        self.lineEditRedshift = QtWidgets.QLineEdit(self.groupBox_4)
        self.lineEditRedshift.setObjectName("lineEditRedshift")
        self.horizontalLayout_2.addWidget(self.lineEditRedshift)
        self.horizontalSliderRedshift = QtWidgets.QSlider(self.groupBox_4)
        self.horizontalSliderRedshift.setMaximum(10000)
        self.horizontalSliderRedshift.setOrientation(QtCore.Qt.Horizontal)
        self.horizontalSliderRedshift.setObjectName("horizontalSliderRedshift")
        self.horizontalLayout_2.addWidget(self.horizontalSliderRedshift)
        self.horizontalLayout_2.setStretch(6, 1)
        self.horizontalLayout_2.setStretch(7, 6)
        self.verticalLayout_9.addLayout(self.horizontalLayout_2)
        self.graphicsView_2 = PlotWidget(self.groupBox_4)
        self.graphicsView_2.setObjectName("graphicsView_2")
        self.verticalLayout_9.addWidget(self.graphicsView_2)
        self.graphicsView = PlotWidget(self.groupBox_4)
        self.graphicsView.setObjectName("graphicsView")
        self.verticalLayout_9.addWidget(self.graphicsView)
        self.verticalLayout_9.setStretch(2, 1)
        self.verticalLayout_9.setStretch(3, 5)
        self.verticalLayout_2.addWidget(self.groupBox_4)
        self.verticalLayout_2.setStretch(0, 3)
        self.verticalLayout_2.setStretch(1, 11)
        self.horizontalLayout_3.addLayout(self.verticalLayout_2)
        self.horizontalLayout_3.setStretch(0, 9)
        self.horizontalLayout_3.setStretch(1, 32)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 1205, 22))

def __init__(self):
        super().__init__()
        self.xaxis = DateAxis(orientation='bottom')
        self.xaxis.setStyle(tickTextOffset=7, textFillLimits=[(0, 0.80)])
        self.yaxis = PriceAxis()

        self.layout = QtGui.QVBoxLayout(self)
        self.layout.setContentsMargins(0, 0, 0, 0)

        self.chart = pg.PlotWidget(
            axisItems={'bottom': self.xaxis, 'right': self.yaxis},
            enableMenu=False,
        )
        self.chart.setFrameStyle(QtGui.QFrame.StyledPanel | QtGui.QFrame.Plain)
        self.chart.getPlotItem().setContentsMargins(*CHART_MARGINS)
        self.chart.showGrid(x=True, y=True)
        self.chart.hideAxis('left')
        self.chart.showAxis('right')

        self.chart.setCursor(QtCore.Qt.BlankCursor)
        self.chart.sigXRangeChanged.connect(self._update_yrange_limits)

        self.layout.addWidget(self.chart)

# Too lazy for recursion:
for child in p.children():
    child.sigValueChanging.connect(valueChanging)
    for ch2 in child.children():
        ch2.sigValueChanging.connect(valueChanging)



#w5 = pg.ImageView()
#w5.setImage(np.random.normal(size=(100,100)))
dock5.addWidget(w5)



w6 = pg.PlotWidget(title=u"\u03b2 x,y") # beta
w6.plot([t.s for t in tws],[t.beta_x for t in tws], pen=(255, 0, 0))
w6.plot([t.s for t in tws],[t.beta_y for t in tws], pen=(0, 255, 0))

d6.addWidget(w6)



win.show()



## Start Qt event loop unless running in interactive mode or using pyside.
if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

self.plot_widget.block = self

        self.plot_widget.setLabel('bottom', 'Frequency', units='Hz')
        self.plot_widget.setLabel("left", "Time", units='s')

        #TODO: listener for this
        #self.plot_widget.setYRange(-self.history_size / self.sampling_rate, 0)

        #self.plot_widget.setLimits(xMin=0, yMax=0)
        #self.plot_widget.showButtons()
        #self.waterfallPlotWidget.setAspectLocked(True)
        #self.waterfallPlotWidget.setDownsampling(mode="peak")
        #self.waterfallPlotWidget.setClipToView(True)
        
        # Setup histogram widget (for controlling waterfall plot levels and gradients)
        self.histogram = pg.PlotWidget(title='Histogram')
        self.waterfallHistogram = pg.HistogramLUTItem()
        self.histogram.addItem(self.waterfallHistogram)
        self.waterfallHistogram.gradient.loadPreset("flame")
        #self.waterfallHistogram.setHistogramRange(-50, 0)
        #self.waterfallHistogram.setLevels(-50, 0)

        self.waterfallImg = pg.ImageItem()
        self.plot_widget.clear()
        self.plot_widget.addItem(self.waterfallImg)      
        self.waterfallHistogram.setImageItem(self.waterfallImg)

        self.setup_range()

        self.update_counter = 0

legendArea = DockArea()
            dCurve     = Dock("", size=(250,600))
            dInfo      = Dock("", size=(250,900))

            legendArea.addDock(dCurve, 'top'   )
            legendArea.addDock(dInfo,  'bottom')

            wCur = QtGui.QWidget();
            wCur.setLayout(libs.perf_reader.buildLegendLayout(path))

            sCur = QtGui.QScrollArea()
            sCur.setWidget(wCur)
            sCur.setWidgetResizable(True)
            dInfo.addWidget(sCur)

            wLegend = pg.PlotWidget(title="BER preview")
            wLegend.setLogMode(False, True)
            wLegend.plot(x=data_snr, y=data_ber,  pen=pen, name='BER plot')
            wLegend.showGrid(False, False)
            dCurve.addWidget(wLegend)

            self.plot_lege.addTab(legendArea, 'Curve ' + str(icolor +1))

# Button for loading .dat file
load_btn = pg.QtGui.QPushButton("Load...")
w1l.addWidget(load_btn, 0, 0)

# Tree for displaying .pul structure
tree = pg.QtGui.QTreeWidget()
tree.setHeaderLabels(['Node', 'Label'])
tree.setColumnWidth(0, 200)
w1l.addWidget(tree, 1, 0)

# Tree for displaying metadata for selected node
data_tree = pg.DataTreeWidget()
vsplit.addWidget(data_tree)

# Plot for displaying trace data
plot = pg.PlotWidget()
hsplit.addWidget(plot)

# Resize and show window
hsplit.setStretchFactor(0, 400)
hsplit.setStretchFactor(1, 600)
win.resize(1200, 800)
win.show()


def load_clicked():
    # Display a file dialog to select a .dat file
    file_name = pg.QtGui.QFileDialog.getOpenFileName()
    if file_name == '':
        return
    load(file_name)

def replot(self):
        """
        Update plot
        """
        pg.PlotWidget.update(self)
        return

box, self, "component_x", callback=self._component_changed)

        box = gui.vBox(axes_box, "Axis Y", margin=0)
        box.setFlat(True)
        self.axis_y_cb = gui.comboBox(
            box, self, "component_y", callback=self._component_changed)

        self.infotext = gui.widgetLabel(
            gui.vBox(self.controlArea, "Contribution to Inertia"), "\n"
        )

        gui.auto_send(self.controlArea, self, "auto_commit")

        gui.rubber(self.controlArea)

        self.plot = pg.PlotWidget(background="w")
        self.plot.setMenuEnabled(False)
        self.mainArea.layout().addWidget(self.plot)

def addPlots(self):
        """
        Initializes the GUIs plots and labels on startup.
        """
        #self.objective_func_pv = "test_obj"
        #setup plot 1 for obj func monitor
        self.plot1 = pg.PlotWidget(title="Objective Function Monitor", labels={'left': str(self.objective_func_pv), 'bottom':"Time (seconds)"})
        self.plot1.showGrid(1, 1, 1)
        self.plot1.getAxis('left').enableAutoSIPrefix(enable=False) # stop the auto unit scaling on y axes
        layout = QtGui.QGridLayout()
        self.ui.widget_2.setLayout(layout)
        layout.addWidget(self.plot1, 0, 0)

        #setup plot 2 for device monitor
        self.plot2 = pg.PlotWidget(title="Device Monitor", labels={'left': "Device (Current - Start)", 'bottom': "Time (seconds)"})
        self.plot2.showGrid(1, 1, 1)
        self.plot2.getAxis('left').enableAutoSIPrefix(enable=False) # stop the auto unit scaling on y axes
        layout = QtGui.QGridLayout()
        self.ui.widget_3.setLayout(layout)
        layout.addWidget(self.plot2, 0, 0)

        #legend for plot 2
        self.leg2 = customLegend(offset=(75, 20))
        self.leg2.setParentItem(self.plot2.graphicsItem())

        #create the obj func line object
        color = QtGui.QColor(0, 255, 255)
        pen=pg.mkPen(color, width=3)
        self.obj_func_line = pg.PlotCurveItem(x=[], y=[], pen=pen, antialias=True)
        self.obj_func_value = pg.PlotCurveItem(x=[], y=[], pen=pg.mkPen(QtGui.QColor(255, 255, 51), width=3),
                                               antialias=True, name="value")