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pythonmatplotlibplotlabelsubplot

How to set properties on matplotlib subplots


I'm adding a matplotlib figure to a canvas so that I may integrate it with pyqt in my application. I was looking around and using plt.add_subplot(111) seem to be the way to go(?) But I cannot add any properties to the subplot as I may with an "ordinary" plot.

figure setup

figure1 = plt.figure()
canvas1 = FigureCanvas(figure1)
graphtoolbar1 = NavigationToolbar(canvas1, frameGraph1)

hboxlayout = qt.QVBoxLayout()
        
hboxlayout.addWidget(graphtoolbar1)
hboxlayout.addWidget(canvas1)
        
frameGraph1.setLayout(hboxlayout)

creating subplot and adding data

df = quandl.getData(startDate, endDate, company)
          
ax = figure1.add_subplot(111)
ax.hold(False)
ax.plot(df['Close'], 'b-')
ax.legend(loc=0)
ax.grid(True)

I'd like to set x and y labels, but if I do ax.xlabel("Test")

AttributeError: 'AxesSubplot' object has no attribute 'ylabel'

which is possible if I did it by not using subplot

plt.figure(figsize=(7, 4))
plt.plot(df['Close'], 'k-')
plt.grid(True)
plt.legend(loc=0)
plt.xlabel('value')
plt.ylabel('frequency')
plt.title('Histogram')
locs, labels = plt.xticks()
plt.setp(labels, rotation=25)
plt.show()

So I guess my question is, is it not possible to modify subplots further? Or is it possible for me to plot graphs in a pyqt canvas, without using subplots so that I may benefit from more properties for my plots?


Solution

  • plt.subplot returns a subplot object which is a type of axes object. It has two methods for adding axis labels: set_xlabel and set_ylabel:

    ax = plt.subplot('111')
    ax.set_xlabel('X Axis')
    ax.set_ylabel('Y Axis')
    

    You could also call plt.xlabel and plt.ylabel (like you did before) and specify the axes to which you want the label applied.

    ax = plt.subplot('111')
    plt.xlabel('X Axis', axes=ax)
    plt.ylabel('Y Axis', axes=ax)
    

    Since you only have one axes, you could also omit the axes kwarg since the label will automatically be applied to the current axes if one isn't specified.

    ax = plt.subplot('111')
    plt.xlabel('X Axis')
    plt.ylabel('Y Axis')