不支持的操作数类型 -："str"和"float"

Question

我有此数据：

new.csv：

X         Y
230.1   22.1
44.5    10.4
17.2    9.3
151.5   18.5
180.8   12.9
8.7 7.2
57.5    11.8
120.2   13.2
8.6 4.8
199.8   10.6
66.1    8.6
214.7   17.4
23.8    9.2
97.5    9.7
204.1   19
195.4   22.4
67.8    12.5
281.4   24.4
69.2    11.3

我正在尝试应用线性回归模型。

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
from sklearn import linear_model, cross_validation
import random 
data = pd.read_csv('./data/new.csv', names=['X', 'Y'], header=0)

fig = plt.figure()
ax = plt.axes()
x = data.loc[:,'X'].to_frame()
y = data.loc[:,'Y'].to_frame()
x_train, x_test, y_train, y_test = cross_validation.train_test_split(x, y, test_size=0.3, random_state=0)
regr = linear_model.LinearRegression()
regr.fit(x_train, y_train)

ax.set(xlabel='X', ylabel='Y', title='X vs Y')
ax.scatter(x_test,y_test, alpha=0.5, cmap='viridis')
ax.plot(x_test, regr.predict(x_test), color='red', linewidth=2)

直到这里一切都很好。我尝试添加错误栏的那一刻：

plt.errorbar(x_test,y_test, yerr=1, fmt='o');

我正在收到标题中的错误。

完整错误是：

TypeError                                 Traceback (most recent call last)
<ipython-input-29-cf35bd0c650f> in <module>()
     29 
     30 #dy=1
---> 31 plt.errorbar(x_test,y_test, yerr=1);
../anaconda2/envs/python3/lib/python3.5/site-packages/matplotlib/pyplot.py in errorbar(x, y, yerr, xerr, fmt, ecolor, elinewidth, capsize, barsabove, lolims, uplims, xlolims, xuplims, errorevery, capthick, hold, data, **kwargs)
   2835                           xlolims=xlolims, xuplims=xuplims,
   2836                           errorevery=errorevery, capthick=capthick, data=data,
-> 2837                           **kwargs)
   2838     finally:
   2839         ax.hold(washold)
../anaconda2/envs/python3/lib/python3.5/site-packages/matplotlib/__init__.py in inner(ax, *args, **kwargs)
   1817                     warnings.warn(msg % (label_namer, func.__name__),
   1818                                   RuntimeWarning, stacklevel=2)
-> 1819             return func(ax, *args, **kwargs)
   1820         pre_doc = inner.__doc__
   1821         if pre_doc is None:
../anaconda2/envs/python3/lib/python3.5/site-packages/matplotlib/axes/_axes.py in errorbar(self, x, y, yerr, xerr, fmt, ecolor, elinewidth, capsize, barsabove, lolims, uplims, xlolims, xuplims, errorevery, capthick, **kwargs)
   2924 
   2925         if yerr is not None:
-> 2926             lower, upper = extract_err(yerr, y)
   2927             # select points without upper/lower limits in y and
   2928             # draw normal errorbars for these points
../anaconda2/envs/python3/lib/python3.5/site-packages/matplotlib/axes/_axes.py in extract_err(err, data)
   2873             # using list comps rather than arrays to preserve units
   2874             low = [thisx - thiserr for (thisx, thiserr)
-> 2875                    in cbook.safezip(data, err)]
   2876             high = [thisx + thiserr for (thisx, thiserr)
   2877                     in cbook.safezip(data, err)]
../anaconda2/envs/python3/lib/python3.5/site-packages/matplotlib/axes/_axes.py in <listcomp>(.0)
   2872                                      "dimensions as x, or 2xN.")
   2873             # using list comps rather than arrays to preserve units
-> 2874             low = [thisx - thiserr for (thisx, thiserr)
   2875                    in cbook.safezip(data, err)]
   2876             high = [thisx + thiserr for (thisx, thiserr)
TypeError: unsupported operand type(s) for -: 'str' and 'int'

Answer 1

我尝试了：

plt.errorbar(x_test.values, y_test.values, yerr=1, fmt='o');

它有效！