我正在尝试使用matplotlib创建一个世界上5种口语的％发言者的垂直条形图。为了更好地突出最高的口语，我改变了酒吧的颜色。我还想将相应的x轴刻度标签更改为更暗的颜色。一切都很好，除了我似乎无法改变x轴刻度标签颜色。
我的软件：
Windows
Anaconda 4.3.0 x64，包含：
- IPython 5.1.0
- Python 3.6.0
- matplotlib 2.0.0
- Spyder 3.1.3
我的尝试/故障排除：
我已经使用plt.gca().get_xticklabels().set_color()在Formatting only selected tick labels尝试了解决方案，看起来它完全符合我的要求。不幸的是，即使颜色值似乎发生变化，这也不会改变x轴刻度标签的颜色：
#Does not change label color, but does show red when called
print("Color before change: " + plt.gca().get_xticklabels()[-3].get_color())
plt.gca().get_xticklabels()[-3].set_color('red') #Does not change the label
print("Color after change: " + plt.gca().get_xticklabels()[-3].get_color()) #Does show the value as 'red'
正如评论所证明的那样，x轴刻度标签不会变为红色，但.get_color（）方法会返回red：
Color before change: grey
Color after change: red
我尝试改变get_xticklabels()[index]的索引，但所有索引都与列出的索引相同。
上面的答案提到索引并不总是直截了当，所以我通过打印x轴刻度标签的文本值做了一些故障排除：
for item in plt.gca().get_xticklabels():
print("Text: " + item.get_text())
每个项目都是空白的：
In [9]: runfile('x')
Text:
Text:
Text:
Text:
Text:
Text:
Text:
在我看来，标签正在其他地方举行，或者可能尚未填充。我尝试过使用get_xmajorticklabels()和get_xminorticklabels()进行类似的搜索。
我还尝试将颜色列表直接传递给labelcolor参数：
label_col_vals = ['grey','grey','black','grey','grey']
plt.gca().tick_params(axis='x', labelcolor=label_col_vals)
但是这只会返回我认为是图形内存位置的内容：
<matplotlib.figure.Figure at 0x14e297d69b0>
如果尝试使用get_xticklabels().set_color()方法更改单个x轴刻度标签颜色，这也会导致错误：
ValueError: could not convert string to float: 'grey'
传递单个颜色值（如下所示）有效，但这会将所有x轴刻度标签设置为相同的颜色：
plt.gca().tick_params(axis='x', labelcolor='grey')
的问题：
如何更改单个x轴刻度标签的颜色？
将列表传递给labelcolor或让get_xticklabels().set_color()工作会更好，但另一种方法也不错。
的代码：
'''
@brief autoprint height labels for each bar
@detailed The function determines if labels need to be on the inside or outside
of the bar. The label will always be centered with respect to he width of the
bar
@param bars the object holding the matplotlib.pyplot.bar objects
'''
def AutoLabelBarVals(bars):
import matplotlib.pyplot as plt
ax=plt.gca()
# Get y-axis height to calculate label position from.
(y_bottom, y_top) = ax.get_ylim()
y_height = y_top - y_bottom
# Add the text to each bar
for bar in bars:
height = bar.get_height()
label_position = height + (y_height * 0.01)
ax.text(bar.get_x() + bar.get_width()/2., label_position,
'%d' % int(height),
ha='center', va='bottom')
import matplotlib.pyplot as plt
import numpy as np
plt.figure()
'''
@note data from https://www.ethnologue.com/statistics/size
'''
languages =['English','Hindi','Mandarin','Spanish','German']
pos = np.arange(len(languages))
percent_spoken = [372/6643, 260/6643, 898/6643, 437/6643, 76.8/6643]
percent_spoken = [x*100 for x in percent_spoken]
'''
@brief change ba colors, accentuate Mandarin
'''
bar_colors = ['#BAD3C8']*(len(languages)-1)
bar_colors.insert(2,'#0C82D3')
bars = plt.bar(pos, percent_spoken, align='center', color=bar_colors)
'''
@brief Soften the other bars to highlight Mandarin
'''
plt.gca().yaxis.label.set_color('grey')
label_colors = ['grey','grey','black','grey','grey']
#plt.gca().tick_params(axis='x', labelcolor=label_colors) #Does not work
plt.gca().tick_params(axis='x', labelcolor='grey') #Works
'''
@brief Try to change colors as in https://stackoverflow.com/questions/41924963/formatting-only-selected-tick-labels
'''
# Try to output values of text to pinpoint which one needs changed
for item in plt.gca().get_xticklabels():
print("Text: " + item.get_text())
print(plt.gca().get_xticklabels()[0].get_text())
'''
@warning If trying to set the x-axis tick labels via list, this code block will fail
'''
print("Color before change: " + plt.gca().get_xticklabels()[1].get_color())
plt.gca().get_xticklabels()[1].set_color('red') #Does not change the label
print("Color after change: " + plt.gca().get_xticklabels()[1].get_color()) #Does show the value as 'red'
'''
@warning If trying to set the x-axis tick labels via list, this code block will fail
'''
plt.xticks(pos, languages)
plt.title('Speakers of Select Languages as % of World Population')
# remove all the ticks (both axes), and tick labels on the Y axis
plt.tick_params(top='off', bottom='off', left='off', right='off', labelleft='off', labelbottom='on', color='grey')
'''
@brief remove the frame of the chart
'''
for spine in plt.gca().spines.values():
spine.set_visible(False)
# Show % values on bars
AutoLabelBarVals(bars)
plt.show()
答案 0 :(得分：3)
ticklabels可能会在脚本的过程中发生变化。因此，建议在脚本的最末端设置颜色，此时不再进行任何更改。
from __future__ import division
import matplotlib.pyplot as plt
import numpy as np
def AutoLabelBarVals(bars):
ax=plt.gca()
(y_bottom, y_top) = ax.get_ylim()
y_height = y_top - y_bottom
for bar in bars:
height = bar.get_height()
label_position = height + (y_height * 0.01)
ax.text(bar.get_x() + bar.get_width()/2., label_position,
'%d' % int(height),
ha='center', va='bottom')
plt.figure()
languages =['English','Hindi','Mandarin','Spanish','German']
pos = np.arange(len(languages))
percent_spoken = [372/6643, 260/6643, 898/6643, 437/6643, 76.8/6643]
percent_spoken = [x*100 for x in percent_spoken]
bar_colors = ['#BAD3C8']*(len(languages)-1)
bar_colors.insert(2,'#0C82D3')
bars = plt.bar(pos, percent_spoken, align='center', color=bar_colors)
plt.gca().yaxis.label.set_color('grey')
plt.gca().tick_params(axis='x', labelcolor='grey') #Works
plt.xticks(pos, languages)
plt.title('Speakers of Select Languages as % of World Population')
plt.tick_params(top='off', bottom='off', left='off', right='off',
labelleft='off', labelbottom='on', color='grey')
for spine in plt.gca().spines.values():
spine.set_visible(False)
AutoLabelBarVals(bars)
plt.gca().get_xticklabels()[1].set_color('red')
plt.show()
答案 1 :(得分：1)
使用plt.tick_params拨打color='grey'会覆盖颜色设置。
您的打印报表不起作用，因为它们是在您使用plt.xticks()设置x刻度标签之前发生的。在调用plt.bars之后，将这两行移动到您的代码应该有效。
bars = plt.bar(pos, percent_spoken, align='center', color=bar_colors)
plt.xticks(pos, languages)
plt.tick_params(top='off', bottom='off', left='off', right='off', labelleft='off', labelbottom='on', color='grey')