无法解包不可迭代的 AxesSubplot 对象-Matplotlib

Question

I am making a function in python which allows me to create two parallel graphs and they share their 2 axes:

def PlotManager(data1,data2,fig):
    f, (ax1, ax2) = fig.subplots(2, 1, sharey=True,sharex=True)

    #Plot1 sopra
    x_axis = data1.index
    #Plot and shade the area between the upperband and the lower band grey
    ax1.fill_between(x_axis,data1['Upper'],data1['Lower'], color = 'grey', alpha= 0.5)
    #Plot the closing price and the moving average
    ax1.plot(x_axis,data1['Close'],color = 'gold',lw = 3,label = 'Close Price', alpha= 0.5)
    ax1.plot(x_axis,data1['SMA'],color = 'blue',lw = 3,label = 'Simple Moving Average', alpha= 0.5)
    ax1.scatter(x_axis,data1['Buy'],color="green", lw=3,label="Buy",marker = "^", alpha=1)
    ax1.scatter(x_axis,data1['Sell'],color="red", lw=3,label="Sell",marker = "v", alpha = 1)
    #Set the title and show the image
    ax1.set_title("Bollinger Band for Amazon")
    plt.xticks(rotation = 45)

    #Plot 2 Sotto
    ax2.set_title('RSI_Plot')
    ax2.plot(x_axis,data2['RSI'])
    ax2.axhline(0,linestyle='--',alpha=0.5, color="grey")
    ax2.axhline(10,linestyle='--',alpha=0.5, color="orange")
    ax2.axhline(20,linestyle='--',alpha=0.5, color="green")
    ax2.axhline(30,linestyle='--',alpha=0.5, color="red")
    ax2.axhline(70,linestyle='--',alpha=0.5, color="red")
    ax2.axhline(80,linestyle='--',alpha=0.5, color="green")
    ax2.axhline(90,linestyle='--',alpha=0.5, color="orange")
    ax2.axhline(100,linestyle='--',alpha=0.5, color="grey")

But gives me the cannot unpack non-iterable AxesSubplot object error:

[Command: python -u C:\Users\Nicolò\Documents\Git\ProgettoTradingBot\ProgettoTradeBot\GUIprova2.py]
C:\Users\Nicolò\Documents\Git\ProgettoTradingBot\ProgettoTradeBot\BollingerBandsFinal.py:63: MatplotlibDeprecationWarning: Adding an axes using the same arguments as a previous axes currently reuses the earlier instance.  In a future version, a new instance will always be created and returned.  Meanwhile, this warning can be suppressed, and the future behavior ensured, by passing a unique label to each axes instance.
  ax = f.add_subplot(111)
C:\Users\Nicolò\Documents\Git\ProgettoTradingBot\ProgettoTradeBot\BollingerBandsFinal.py:63: MatplotlibDeprecationWarning: Adding an axes using the same arguments as a previous axes currently reuses the earlier instance.  In a future version, a new instance will always be created and returned.  Meanwhile, this warning can be suppressed, and the future behavior ensured, by passing a unique label to each axes instance.
  ax = f.add_subplot(111)
Traceback (most recent call last):
  File "C:\Users\Nicolò\AppData\Local\Programs\Python\Python38\lib\site-packages\matplotlib\cbook\__init__.py", line 196, in process
    func(*args, **kwargs)
  File "C:\Users\Nicolò\AppData\Local\Programs\Python\Python38\lib\site-packages\matplotlib\animation.py", line 951, in _start
    self._init_draw()
  File "C:\Users\Nicolò\AppData\Local\Programs\Python\Python38\lib\site-packages\matplotlib\animation.py", line 1743, in _init_draw
    self._draw_frame(next(self.new_frame_seq()))
  File "C:\Users\Nicolò\AppData\Local\Programs\Python\Python38\lib\site-packages\matplotlib\animation.py", line 1766, in _draw_frame
    self._drawn_artists = self._func(framedata, *self._args)
  File "C:\Users\Nicolò\Documents\Git\ProgettoTradingBot\ProgettoTradeBot\GUIprova2.py", line 48, in animate
    PlotManager(BollingerBands(df,f),RSI(df,f2),f)
  File "C:\Users\Nicolò\Documents\Git\ProgettoTradingBot\ProgettoTradeBot\mostraGrafici.py", line 7, in PlotManager
    f, (ax1, ax2) = fig.subplots(2, 1, sharey=True,sharex=True)
TypeError: cannot unpack non-iterable AxesSubplot object

How can i handle to this error?

Answer 1

The value of plt.subplots(2, 1, ...) is a tuple figure, array(subplot0, subplot1) so that you can unpack correctly to a figure and two subplots.

On the contrary the value of fig.subplots(2, 1, ...) is subplot0, subplot1 (because you ALREADY have the figure…) and when you try to unpack it's equivalent to

f = subplot0
ax0, ax1 = subplot1

and this leads to TypeError: cannot unpack non-iterable AxesSubplot object

---

Because you are not using the object labeled as f in the following, you should write

ax1, ax2 = fig.subplots(2, 1, sharey=True,sharex=True)