Matplotlib - 在网格中放置饼图

Question

我正在尝试将饼图组织在一个网格中，在左侧的另一列中，我在特定行的饼图上写了一些相关数据。现在我的代码是：

data = [[0.3,0.3,0.3,0.1],[0.2,0.2,0.2,0.4],[0.1,0.1,0.4,0.4]]


def main():
    createPieCharts(data)
    return 0


def createPieCharts(data,piecharts_fname="piecharts"):
    """ """
    import datetime
    from matplotlib.backends.backend_pdf import PdfPages
    import matplotlib.pyplot as plt
    areas = ['Arava','Lotz','Paran','Ramon']
    thresholds = [0.0,0.01,0.02]
    num_columns = len(areas)
    num_rows    = len(thresholds)
    with PdfPages(piecharts_fname+'.pdf') as pdf:
        fig, ax = plt.subplots(num_rows,num_columns)
#            fig.suptitle('Raining Hogs and Dogs', bbox={'facecolor':'0.8', 'pad':5})
        labels = ['Frogs', 'Hogs', 'Dogs', 'Logs']
        for i,threshold in enumerate(thresholds):
            fracs = data[i]
            for j,area in enumerate(areas):
                ax[i,j].set_title(area)
                ax[i,j].pie(fracs, labels=labels,
                            autopct='%1.1f%%', shadow=True, startangle=90)
                ax[i,j].set_aspect('equal')
        plt.tight_layout(pad=0.4, w_pad=0.5, h_pad=1.0)
        pdf.savefig(fig)
        plt.close()
        # Adding metadata for PDF file
        d = pdf.infodict()
        d['Title'] = 'Pie charts'
        d['CreationDate'] = datetime.datetime.today()

if __name__ == '__main__':
    main()

结果看起来像这样 虽然我希望它在左边有另一列，就像在这个例子中一样 -

什么是聪明的做法？

Answer 1

添加一个额外的列，并将您的文本放在那里。

然后，您只需关闭左列 (ax.set_axis_off()) 中的坐标轴和刻度线，并使用ax.text 添加文本标签。

请注意，您还需要为绘制饼图的其他轴的 j 索引添加 1。

这是脚本中的函数，已修改：

def createPieCharts(data,piecharts_fname="piecharts"):
    """ """
    import datetime
    from matplotlib.backends.backend_pdf import PdfPages
    import matplotlib.pyplot as plt
    areas = ['Arava','Lotz','Paran','Ramon']
    thresholds = [0.0,0.01,0.02]
    num_columns = len(areas) + 1                                # Add extra column for text
    num_rows    = len(thresholds)
    with PdfPages(piecharts_fname+'.pdf') as pdf:
        fig, ax = plt.subplots(num_rows,num_columns)
#            fig.suptitle('Raining Hogs and Dogs', bbox={'facecolor':'0.8', 'pad':5})
        labels = ['Frogs', 'Hogs', 'Dogs', 'Logs']
        for i,threshold in enumerate(thresholds):
            fracs = data[i]
            ax[i,0].set_axis_off()                                  # Turn off axes & ticks
            ax[i,0].text(0.5,0.5,threshold,ha='center',va='center') # Add text
            for j,area in enumerate(areas):
                ax[i,j+1].set_title(area)                           # Add 1 to j index
                ax[i,j+1].pie(fracs, labels=labels,                 # Add 1 to j index
                            autopct='%1.1f%%', shadow=True, startangle=90)
                ax[i,j+1].set_aspect('equal')                       # Add 1 to j index
        plt.tight_layout(pad=0.4, w_pad=0.5, h_pad=1.0)
        pdf.savefig(fig)
        plt.close()
        # Adding metadata for PDF file
        d = pdf.infodict()
        d['Title'] = 'Pie charts'
        d['CreationDate'] = datetime.datetime.today()

Answer 2

如果您对轴对象使用特殊函数 is_first_col 标记 y 轴并使用 is_last_row 标记 x 轴，这是可能的：

def createPieCharts(data,piecharts_fname="piecharts"):
    """ """
    import datetime
    from matplotlib.backends.backend_pdf import PdfPages
    import matplotlib.pyplot as plt
    areas = ['Arava','Lotz','Paran','Ramon']
    thresholds = [0.0,0.01,0.02]
    num_columns = len(areas)
    num_rows    = len(thresholds)
    val = 0. # to y axis labels
    with PdfPages(piecharts_fname+'.pdf') as pdf:
        fig, ax = plt.subplots(num_rows,num_columns)
        labels = ['Frogs', 'Hogs', 'Dogs', 'Logs']
        for i,threshold in enumerate(thresholds):
            fracs = data[i]
            for j,area in enumerate(areas):
                ax[i,j].set_title(area)
                ax[i,j].pie(fracs, labels=labels,
                            autopct='%1.1f%%', shadow=True, startangle=90)
                ax[i,j].set_aspect('equal')
                # label y axis
                if ax[i,j].is_first_col():
                    ax[i,j].set_ylabel(str(val), fontsize = 9, rotation = 0)
                    val += .01
        plt.tight_layout(pad=0.4, w_pad=0.5, h_pad=1.0)
        pdf.savefig(fig)
        plt.close()
        # Adding metadata for PDF file
        d = pdf.infodict()
        d['Title'] = 'Pie charts'
        d['CreationDate'] = datetime.datetime.today()