Matplotlib，设置坐标刻度大小，字体/设置图例大小及字体/设置纵横坐标名称及字体及大小

基础绘图案例

# coding: utf-8
import matplotlib.pyplot as plt

# figsize = 11, 9
# figure, ax = plt.subplots(figsize = figsize)
x1 =[0,5000,10000, 15000, 20000, 25000, 30000, 35000, 40000, 45000, 50000, 55000]
y1=[0, 223, 488, 673, 870, 1027, 1193, 1407, 1609, 1791, 2113, 2388]
x2 = [0, 5000, 10000, 15000, 20000, 25000, 30000, 35000, 40000, 45000, 50000, 55000]
y2 = [0, 214, 445, 627, 800, 956, 1090, 1281, 1489, 1625, 1896, 2151]

# 设置输出的图片大小
figsize = 11, 9
figure, ax = plt.subplots(figsize=figsize)

# 在同一幅图片上画两条折线
A, = plt.plot(x1, y1, '-r', label='A', linewidth=5.0)
B, = plt.plot(x2, y2, 'b-.', label='B', linewidth=5.0)

# 设置图例并且设置图例的字体及大小
font1 = {
    'family': 'Times New Roman',
         'weight': 'normal',
         'size': 23,
         }
legend = plt.legend(handles=[A, B], prop=font1)

# 设置坐标刻度值的大小以及刻度值的字体
plt.tick_params(labelsize=23)
labels = ax.get_xticklabels() + ax.get_yticklabels()
# print labels
[label.set_fontname('Times New Roman') for label in labels]
# 设置横纵坐标的名称以及对应字体格式
font2 = {
    'family': 'Times New Roman',
         'weight': 'normal',
         'size': 30,
         }
plt.xlabel('round', font2)
plt.ylabel('value', font2)
plt.show()

python-增加matplotlib中图例行的线宽

我知道，如果更改线的线宽，则会在图例中自动更新。但是，我只想更改图例的线宽而不影响绘图。

现在有如下四种解决方案

获取leg对象

#这是一个简单的例子：
import numpy as np
import matplotlib.pyplot as plt

# make some data
x = np.linspace(0, 2*np.pi)
y1 = np.sin(x)
y2 = np.cos(x)

# plot sin(x) and cos(x)
p1 = plt.plot(x, y1, 'b-', linewidth=1.0)
p2 = plt.plot(x, y2, 'r-', linewidth=1.0)

# make a legend for both plots
leg = plt.legend([p1, p2], ['sin(x)', 'cos(x)'], loc=1)

# set the linewidth of each legend object
for legobj in leg.legendHandles:
	legobj.set_linewidth(2.0)

plt.show()

pyplot提供的api

@Brendan Wood的方法使用pyplot提供的api。在matplotlib中，首选使用轴的面向对象样式。 下面是如何使用axes方法实现此目的的方法。

import numpy as np
import matplotlib.pyplot as plt

# make some data
x = np.linspace(0, 2*np.pi)
y1 = np.sin(x)
y2 = np.cos(x)
fig, ax = plt.subplots()
ax.plot(x, y1, linewidth=1.0, label='sin(x)'
ax.plot(x, y2, linewidth=1.0, label='cos(x)')

leg = ax.legend()
for line in leg.get_lines():
	line.set_linewidth(4.0)

plt.show()

自定义方案

如果要更改绘图中的所有线条，定义自己的图例处理程序可能会很有用：

import matplotlib.pyplot as plt
from matplotlib import legend_handler
from matplotlib.lines import Line2D
import numpy as np

class MyHandlerLine2D(legend_handler.HandlerLine2D):
	def create_artists(self, legend, orig_handle,xdescent, ydescent, width, height, fontsize,trans):

	xdata, xdata_marker = self.get_xdata(legend, xdescent, ydescent,width, height, fontsize)
	ydata = ((height-ydescent)/2.)*np.ones(xdata.shape, float)

	legline = Line2D(xdata, ydata)
	self.update_prop(legline, orig_handle, legend)

	#legline.update_from(orig_handle)
	#legend._set_artist_props(legline) # after update
	#legline.set_clip_box(None)
	#legline.set_clip_path(None)

	legline.set_drawstyle('default')
	legline.set_marker("")
	legline.set_linewidth(10)
	legline_marker = Line2D(xdata_marker, ydata[:len(xdata_marker)])

	self.update_prop(legline_marker, orig_handle, legend)

	#legline_marker.update_from(orig_handle)
	#legend._set_artist_props(legline_marker)
	#legline_marker.set_clip_box(None)
	#legline_marker.set_clip_path(None)

	legline_marker.set_linestyle('None')
	if legend.markerscale != 1:
		newsz = legline_marker.get_markersize()*legend.markerscale
		legline_marker.set_markersize(newsz)

	# we don't want to add this to the return list because
	# the texts and handles are assumed to be in one-to-one

	# correpondence.
	legline._legmarker = legline_marker
	return [legline, legline_marker]

plt.plot( [0, 1], [0, 1], '-r', lw=1, label='Line' )
plt.legend(handler_map={
    Line2D:MyHandlerLine2D()})
plt.show()

使用画布上艺术家的副本

默认情况下，图例包含行本身。 因此，更改画布中线条的线宽也会更改图例中的线条(反之亦然，因为它们本质上是同一对象)。

一种可能的解决方案是使用画布上艺术家的副本，并仅更改副本的线宽。

import numpy as np
import matplotlib.pyplot as plt
import copy

x = np.linspace(0, 2*np.pi)
y1 = np.sin(x)
y2 = np.cos(x)
fig = plt.figure()

ax = fig.add_subplot(111)
ax.plot(x, y1, c='b', label='y1',linewidth=1.0)
ax.plot(x, y2, c='r', label='y2')

# obtain the handles and labels from the figure
handles, labels = ax.get_legend_handles_labels()

# copy the handles
handles = [copy.copy(ha) for ha in handles ]

# set the linewidths to the copies
[ha.set_linewidth(7) for ha in handles ]

# put the copies into the legend
leg = plt.legend(handles=handles, labels=labels)

plt.savefig('leg_example')
plt.show()

使用handler_map和更新功能

另一种选择是使用handler_map和更新功能。 这以某种方式是自动的，指定处理程序映射将自动使图例中的任何行宽7点。

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.legend_handler import HandlerLine2D

x = np.linspace(0, 2*np.pi)
y1 = np.sin(x)
y2 = np.cos(x)

fig = plt.figure()

ax = fig.add_subplot(111)
ax.plot(x, y1, c='b', label='y1',linewidth=1.0)
ax.plot(x, y2, c='r', label='y2')

linewidth=7

def update(handle, orig):
	handle.update_from(orig)
	handle.set_linewidth(7)

plt.legend(handler_map={
    plt.Line2D : HandlerLine2D(update_func=update)})
plt.show()

结果与上面相同。