当散点图基于数据框并涉及颜色编码数据时，如何在鼠标单击时显示散点图注释？

Question

我有一个数据集：

a   b   c   d
10-Apr-86   Jimmy   1   Silly.doc
11-Apr-86   Minnie  2   Lala.doc
12-Apr-86   Jimmy   3   Goofy.doc
13-Apr-86   Minnie  4   Hilarious.doc
14-Apr-86   Jimmy   5   Joyous.doc
15-Apr-86   Eliot   6   Crackingup.doc
16-Apr-86   Jimmy   7   Funny.doc
17-Apr-86   Eliot   8   Happy.doc
18-Apr-86   Minnie  9   Mirthful.doc

在python 2.7.12中使用以下代码..

df = (pd.read_csv('python.csv'))
df_wanted = pd.pivot_table(
    df,
    index='a',
    columns='b',
    values='c')

df_wanted.index = pd.to_datetime(df_wanted.index)

fig = plt.figure()
ax1 = fig.add_subplot(111)

ax1.scatter(df_wanted.index, df_wanted['Jimmy'], s=50, c='b', marker="s")
ax1.scatter(df_wanted.index,df_wanted['Minnie'], s=50, c='r', marker="o")
ax1.scatter(df_wanted.index,df_wanted['Eliot'], s=50, c='g', marker="8")
plt.legend(loc='upper left');

for k, v in df.set_index('a').iterrows():
    plt.text(k, v['c'], v['d'])
plt.show()

..我可以在matplotlib中创建以下可视化：

问题：这只是一个玩具数据集。当我将此代码应用于具有超过3000个点的真实数据集时，所有数据标签在黑色难以辨认的块中混合在一起。

我希望通过使用代码here来避免此问题，以便在单击时显示数据标签。

我遇到的问题是上述代码的这一部分，

x=[1,2,3,4,5]
y=[6,7,8,9,10]

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1)
scat = ax.scatter(x, y)
DataCursor(scat, x, y)
plt.show()

显然，我需要将“x”和“y”替换为我的数据透视表列，但我不知道如何使scat = ax.scatter(x, y)或DataCursor(scat, x, y)使用我的数据。

我尝试了以下

scat = ax1.scatter(df_wanted.index, df_wanted['Minnie'], s=50, c='b', marker="s")
scat1 = ax1.scatter(df_wanted.index,df_wanted['Jimmy'], s=50, c='r', marker="o")
scat2 = ax1.scatter(df_wanted.index,df_wanted['Eliot'], s=50, c='g', marker="8")

DataCursor(scat,df_wanted.index,df_wanted['Minnie'])
DataCursor(scat1,df_wanted.index,df_wanted['Jimmy'])
DataCursor(scat2,df_wanted.index,df_wanted['Eliot'])
plt.show()

但我收到此错误TypeError: Invalid Type Promotion

更新：我使用here中的代码在控制台中获取文档名称：

from matplotlib.pyplot import figure, show
import numpy as npy
from numpy.random import rand
import pandas as pd

df = (pd.read_csv('python.csv'))
df_wanted = pd.pivot_table(
    df,
    index='a',
    columns='b',
    values='c')

df_wanted.index = pd.to_datetime(df_wanted.index)


if 1: # picking on a scatter plot     (matplotlib.collections.RegularPolyCollection)

    c = 'r'
    c1 = 'b'
    c2 = 'g'
    s = 85 
    y = df_wanted['Minnie']
    z = df_wanted['Jimmy']
    f = df_wanted['Eliot']
    x = df_wanted.index
    def onpick3(event):
        ind = event.ind
        print npy.take(df['d'], ind)

    fig = figure()
    ax1 = fig.add_subplot(111)
    col = ax1.scatter(x, y, s, c, picker=True)
    ax2 = fig.add_subplot(111)
    col = ax1.scatter(x, z, s, c1, picker=True)
    ax3 = fig.add_subplot(111)
    col = ax1.scatter(x, f, s, c2, picker=True)
    plt.legend(loc='upper left')
    #fig.savefig('pscoll.eps')
    fig.canvas.mpl_connect('pick_event', onpick3)

show()

现在的问题是返回的文档名称不准确。我认为问题在于ind编号是针对每个单独的系列。我需要一种方法来组合所有系列，并为其总数分配一个ind数。

Answer 1

我找到了解决方案。我意识到我想要遵循这个例子（Matplotlib scatterplot; colour as a function of a third variable），但需要首先制作一个x值列表和一个y值列表，而不是每个系列的x和y值的单独列表。

import matplotlib.pyplot as plt
from matplotlib.pyplot import figure, show
import numpy as npy
from numpy.random import rand
import pandas as pd

df = (pd.read_csv('python.csv')) #upload dataset

df['a'] = pd.to_datetime(df['a']) #convert date column to useable format

x = list(df['a'].values.flatten()) #get dataframe column data in list format
y= list(df['c'].values.flatten()) #get dataframe column data in list format

var_names = list(df['b'].values.flatten()) #get dataframe column data in list format
var_names1 = list(set(var_names)) #get unique values from column b (names) 


d = {var_names1[n]:n for n in range(len(var_names1))} #generate dictionary that assigns number to each unique name in col B



namesAsNumbers = [d[z] for z in var_names] #replace names with numbers in column B

c=  namesAsNumbers



if 1: # picking on a scatter plot (matplotlib.collections.RegularPolyCollection) # user picks point on scatter

    def onpick3(event):
        ind = event.ind
        print npy.take(df['d'], ind) #print the document name associated with the point that's been picked

    fig = figure()
    ax1 = fig.add_subplot(111)
    col = ax1.scatter(x, y, s= 100, c=c, picker=True)
    #fig.savefig('pscoll.eps')
    fig.canvas.mpl_connect('pick_event', onpick3)
    plt.legend()
show()

我只有问题：似乎无法显示传奇。