Python - 图例值重复

时间:2016-09-27 01:35:34

标签: python matplotlib legend

我正在绘制一个矩阵,如下所示,并且图例一遍又一遍地重复。我尝试过使用numpoints = 1,这似乎没有任何效果。任何提示?

import numpy as np
import matplotlib.pyplot as plt
import pandas as pd
import matplotlib
%matplotlib inline
matplotlib.rcParams['figure.figsize'] = (10, 8) # set default figure size, 8in by 6inimport numpy as np

data = pd.read_csv('data/assg-03-data.csv', names=['exam1', 'exam2', 'admitted'])

x = data[['exam1', 'exam2']].as_matrix()
y = data.admitted.as_matrix()

# plot the visualization of the exam scores here
no_admit = np.where(y == 0)
admit = np.where(y == 1)
from pylab import *
# plot the example figure
plt.figure()
# plot the points in our two categories, y=0 and y=1, using markers to indicated
# the category or output
plt.plot(x[no_admit,0], x[no_admit,1],'yo', label = 'Not admitted', markersize=8, markeredgewidth=1) 
plt.plot(x[admit,0], x[admit,1], 'r^', label = 'Admitted', markersize=8, markeredgewidth=1) 
# add some labels and titles
plt.xlabel('$Exam 1 score$')
plt.ylabel('$Exam 2 score$')
plt.title('Admit/No Admit as a function of Exam Scores')
plt.legend()

1 个答案:

答案 0 :(得分:0)

如果你不提供数据格式的例子,特别是如果你不熟悉大熊猫,那么几乎不可能理解这个问题。 但是,假设您的输入具有以下格式:

x=pd.DataFrame(np.array([np.arange(10),np.arange(10)**2]).T,columns=['exam1','exam2']).as_matrix()
y=pd.DataFrame(np.arange(10)%2).as_matrix()

>>x
array([[ 0,  0],
   [ 1,  1],
   [ 2,  4],
   [ 3,  9],
   [ 4, 16],
   [ 5, 25],
   [ 6, 36],
   [ 7, 49],
   [ 8, 64],
   [ 9, 81]])

>> y
array([[0],
   [1],
   [0],
   [1],
   [0],
   [1],
   [0],
   [1],
   [0],
   [1]])

原因是从DataFrame到矩阵的奇怪转换,我想如果你有矢量(1D数组)就不会发生。 对于我的例子,这是有效的(不确定它是否是最干净的形式,我不知道xy的2D矩阵来自哪里:

plt.plot(x[no_admit,0][0], x[no_admit,1][0],'yo', label = 'Not admitted', markersize=8, markeredgewidth=1) 
plt.plot(x[admit,0][0], x[admit,1][0], 'r^', label = 'Admitted', markersize=8, markeredgewidth=1)