Question

我具有以下功能来绘制图形：

def plot_ATD(DataFrame):
    #Initialise 225V ATD plot
    fig = plt.figure()
    ax = fig.add_subplot(111)
    #take columns from data set and make to list which is passed to matplotlib to plot a graph
    x = DataFrame['Arrival Time (ms)'].tolist()
    y = DataFrame['Intensity'].tolist()
    line, = ax.plot(x,y, 'r-')
    #use numpy to get the max of Intensity, then determine the corresponding arrival time
    ymax = np.max(y)
    xpos = y.index(ymax)
    xmax = x[xpos]
    time = xmax
    #add an annotation point at the maxima giving the arrival time at this position
    # ax.annotate(s=text of annotation, xy=point to annotate, xytext=position to place text
    #              arrowprops=dict(facecolor=color of arrow))
    ax.annotate(s=xmax, xy=(xmax, ymax), xytext=(xmax+5, ymax+5),
                arrowprops=dict(facecolor='orange'),
               )
    #ax.set_ylim(0,600000)
    ax.set_xlim(0,20)
    plt.xlabel('Arrival time (ms)')
    plt.title(DataFrame.name)
    return plt.show()

我正在以下熊猫DataFrame上使用它：

V100 = pd.read_csv('Documents/spreadsheets/Data/100V_9z.csv', names=['Arrival Time (ms)', 'Intensity'])
V125 = pd.read_csv('Documents/spreadsheets/Data/125V_9z.csv', names=['Arrival Time (ms)', 'Intensity'])
V150 = pd.read_csv('Documents/spreadsheets/Data/150V_9z.csv', names=['Arrival Time (ms)', 'Intensity'])
V175 = pd.read_csv('Documents/spreadsheets/Data/175V_9z.csv', names=['Arrival Time (ms)', 'Intensity'])
V200 = pd.read_csv('Documents/spreadsheets/Data/200V_9z.csv', names=['Arrival Time (ms)', 'Intensity'])
V225 = pd.read_csv('Documents/spreadsheets/Data/225V_9z.csv', names=['Arrival Time (ms)', 'Intensity'])

我想让图形标题成为DataFrame的名称，即V100，V125等。

我不确定语法正确或如何执行？请帮忙！

Answer 1

首先，在函数中使用DataFrame作为数据框的名称不是一种好习惯，因为它是pandas.DataFrame类本身的名称。例如，最好将其更改为df。

因此，您可以使用（例如）设置数据框的名称

V100.name = 'V100'

并对所有数据框执行此操作。然后，在您的函数调用（新命名）df.name中，获取先前分配给数据框的名称。

更新

要自动设置数据框名称，您只需执行

file_name = 'Documents/spreadsheets/Data/100V_9z.csv'
V100 = pd.read_csv(file_name, names=['Arrival Time (ms)', 'Intensity'])
V100.name = file_name.split('/')[-1].split('_')[0] # 'V100'

Answer 2

解决方法：

Vs= [v for v in locals() if v.startswith('V')] 
for v in Vs:
    plot(eval(v),title=v)

在创建变量（例如，使用系列（或字典））时，必须使用更清洁的方法（因为eval不安全）：

ser=pd.Series()
ser['V100'] = pd.read_csv('Documents/spreadsheets/Data/100V_9z.csv', \
names=['Arrival Time (ms)', 'Intensity'])

将简化工作。

将DataFrame变量名称作为字符串传递

2 个答案: