Matplotlib：多種顏色的y軸標籤

Question

我想知道製作y標籤的最佳方式，標籤中的每個單詞可以是不同的顏色。

我想這樣做的原因是因爲我將製作包含曲線（電場和矢量勢場）的圖。這些曲線將是不同的顏色，我想在標籤中顯示。以下是一個簡化示例，使用以前的帖子（Matplotlib multiple colours in tick labels）來結束。這篇文章對x軸很好，但是它沒有正確地對y軸進行空間/排序。

另一篇文章有​​類似的問題（Partial coloring of text in matplotlib），但第一個答案似乎並沒有工作，第二個答案讓你將文件保存爲.ps文件。

我的示例代碼

import numpy as np 
import matplotlib.pyplot as plt 
from matplotlib.offsetbox import AnchoredOffsetbox, TextArea, HPacker, VPacker 

ax = plt.subplot(111) 

x = np.linspace(0,10,10) 
y1 = x 
y2 = x**2 

ax.plot(x,y1,color='r',label='data1') 
ax.plot(x,y2,color='b',label='data2') 
ax.set_xticks([]) # empty xticklabels 
ax.set_yticks([]) # empty xticklabels 

# x-axis label 
xbox1 = TextArea("Data1-x ", textprops=dict(color="r", size=15)) 
xbox2 = TextArea("and ", textprops=dict(color="k", size=15)) 
xbox3 = TextArea("Data2-x ", textprops=dict(color="b", size=15)) 

xbox = HPacker(children=[xbox1, xbox2, xbox3], 
        align="center", pad=0, sep=5) 

anchored_xbox = AnchoredOffsetbox(loc=3, child=xbox, pad=0., frameon=False, 
             bbox_to_anchor=(0.3, -0.07), 
             bbox_transform=ax.transAxes, borderpad=0.) 

# y-axis label 
ybox1 = TextArea("Data1-y ", textprops=dict(color="r", size=15,rotation='vertical')) 
ybox2 = TextArea("and ", textprops=dict(color="k", size=15,rotation='vertical')) 
ybox3 = TextArea("Data2-y ", textprops=dict(color="b", size=15,rotation='vertical')) 

ybox = VPacker(children=[ybox1, ybox2, ybox3], 
        align="center", pad=0, sep=5) 

anchored_ybox = AnchoredOffsetbox(loc=8, child=ybox, pad=0., frameon=False, 
             bbox_to_anchor=(-0.08, 0.4), 
             bbox_transform=ax.transAxes, borderpad=0.) 


ax.add_artist(anchored_xbox) 
ax.add_artist(anchored_ybox) 
plt.legend() 
plt.show() 

感謝您的幫助！

Answer 1

你幾乎在那裏。您只需要使用ha ='left'，va ='bottom'來指定文本的對齊方式。 （並翻轉傳遞給VPacker的TextArea對象的順序）。

import numpy as np 
import matplotlib.pyplot as plt 
from matplotlib.offsetbox import AnchoredOffsetbox, TextArea, HPacker, VPacker 

ax = plt.subplot(111) 

x = np.linspace(0,10,10) 
y1 = x 
y2 = x**2 

ax.plot(x,y1,color='r',label='data1') 
ax.plot(x,y2,color='b',label='data2') 

ybox1 = TextArea("Data2-y ", textprops=dict(color="r", size=15,rotation=90,ha='left',va='bottom')) 
ybox2 = TextArea("and ",  textprops=dict(color="k", size=15,rotation=90,ha='left',va='bottom')) 
ybox3 = TextArea("Data1-y ", textprops=dict(color="b", size=15,rotation=90,ha='left',va='bottom')) 

ybox = VPacker(children=[ybox1, ybox2, ybox3],align="bottom", pad=0, sep=5) 

anchored_ybox = AnchoredOffsetbox(loc=8, child=ybox, pad=0., frameon=False, bbox_to_anchor=(-0.08, 0.4), 
            bbox_transform=ax.transAxes, borderpad=0.) 

ax.add_artist(anchored_ybox) 
plt.legend() 
plt.show() 

更重要的是，這裏是使用字符串和顏色的任意列表，使標籤的函數：

import numpy as np 
import matplotlib.pyplot as plt 

def multicolor_ylabel(ax,list_of_strings,list_of_colors,axis='x',anchorpad=0,**kw): 
    """this function creates axes labels with multiple colors 
    ax specifies the axes object where the labels should be drawn 
    list_of_strings is a list of all of the text items 
    list_if_colors is a corresponding list of colors for the strings 
    axis='x', 'y', or 'both' and specifies which label(s) should be drawn""" 
    from matplotlib.offsetbox import AnchoredOffsetbox, TextArea, HPacker, VPacker 

    # x-axis label 
    if axis=='x' or axis=='both': 
     boxes = [TextArea(text, textprops=dict(color=color, ha='left',va='bottom',**kw)) 
        for text,color in zip(list_of_strings,list_of_colors) ] 
     xbox = HPacker(children=boxes,align="center",pad=0, sep=5) 
     anchored_xbox = AnchoredOffsetbox(loc=3, child=xbox, pad=anchorpad,frameon=False,bbox_to_anchor=(0.2, -0.09), 
              bbox_transform=ax.transAxes, borderpad=0.) 
     ax.add_artist(anchored_xbox) 

    # y-axis label 
    if axis=='y' or axis=='both': 
     boxes = [TextArea(text, textprops=dict(color=color, ha='left',va='bottom',rotation=90,**kw)) 
        for text,color in zip(list_of_strings[::-1],list_of_colors) ] 
     ybox = VPacker(children=boxes,align="center", pad=0, sep=5) 
     anchored_ybox = AnchoredOffsetbox(loc=3, child=ybox, pad=anchorpad, frameon=False, bbox_to_anchor=(-0.10, 0.2), 
              bbox_transform=ax.transAxes, borderpad=0.) 
     ax.add_artist(anchored_ybox) 


ax = plt.subplot(111) 

x = np.linspace(0,10,1000) 
y1 = np.sin(x) 
y2 = np.sin(2*x) 

ax.plot(x,y1,color='r') 
ax.plot(x,y2,color='b') 

multicolor_ylabel(ax,('Line1','and','Line2','with','extra','colors!'),('r','k','b','k','m','g'),axis='both',size=15,weight='bold') 

plt.show() 

它仍然需要與立場一些擺弄的「 bbox_to_anchor「關鍵字。