『Python』matplotlib坐标轴应用
1. 设置坐标轴的位置和展示形式
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
mpl.use('Qt5Agg')
mpl.rcParams['font.sans-serif'] = ['SimHei']
mpl.rcParams['font.serif'] = ['SimHei']
mpl.rcParams['axes.unicode_minus'] = False # 解决保存图像是负号'-'显示为方块的问题,或者转换负号为字符串
plt.axes([0.05, 0.7, 0.3, 0.3], frameon=True, facecolor="y", aspect="equal")
plt.plot(np.arange(3), [0, 1, 0], color="blue", linewidth=2, linestyle="--")
plt.ylim(0, 1.5)
plt.axis("image")
plt.axes([0.3, 0.4, 0.3, 0.3], frameon=True, facecolor="y", aspect="equal")
plt.plot(2 + np.arange(3), [0, 1, 0], color="blue", linewidth=2, linestyle="-")
plt.ylim(0, 15)
plt.axis([2.1, 3.9, 0.5, 1.9])
plt.axes([0.55, 0.1, 0.3, 0.3], frameon=True, facecolor="y", aspect="equal")
plt.plot(4 + np.arange(3), [0, 1, 0], color="blue", linewidth=2, linestyle=":")
plt.ylim(0, 1.5)
plt.axis("off")
plt.show()
函数
axes(rect, frameon=True, facecolor="y")
rect = [left, bottom, width, height]
left
和bottom
分别表示坐标轴的左侧边缘和底部边缘距离画布边缘的距离,width
和height
分别表示坐标轴的宽度和高度
left
和width
是画布宽度归一化后的距离,bottom
和height
是画布高度归一化后的距离。
frameon=True
是否显示四条轴脊
facecolor="y"
填充坐标轴背景的颜色函数
axis()
[xmin, xmax, ymin, ymax]
显示坐标轴的范围option
,可取值为
'on'
:打开坐标轴'off'
:关闭坐标轴显示'equal'
:设置相等的比例,y轴和x轴单位刻度对应长度是一样的'scaled'
:通过更改绘图框的尺寸设置相等的缩放比例'tight'
:设置足够大的限制来显示所有数据'auto'
:自动确定'image'
:‘scaled’ with axis limits equal to data limits'square'
:方形图,类似于‘scaled’
,但是强制xmax-xmin = ymax-ymin
2. 坐标轴刻度的显示
import matplotlib.pyplot as plt
import matplotlib as mpl
mpl.rcParams['font.sans-serif'] = ['SimHei']
mpl.rcParams['font.serif'] = ['SimHei']
mpl.rcParams['axes.unicode_minus'] = False # 解决保存图像是负号'-'显示为方块的问题,或者转换负号为字符串
ax1 = plt.subplot(121)
ax1.set_xticks(range(0, 251, 50))
plt.grid(True, axis="x")
ax2 = plt.subplot(122)
ax2.set_xticks([])
plt.grid(True, axis="x")
plt.show()
如果不设置坐标轴刻度,则网格线也不会被设置。设置刻度还包括刻度标签,可以用函数
Axes.set_xticklabels()
和Axes.set_yticklabels()
设置对应刻度线的标签
3. 坐标轴的样式和位置的定制化展示
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
from matplotlib.ticker import FormatStrFormatter
from calendar import day_name
mpl.rcParams['font.sans-serif'] = ['SimHei']
mpl.rcParams['font.serif'] = ['SimHei']
mpl.rcParams['axes.unicode_minus'] = False # 解决保存图像是负号'-'显示为方块的问题,或者转换负号为字符串
fig = plt.figure()
ax = fig.add_axes([0.2, 0.2, 0.7, 0.7])
ax.spines["bottom"].set_position(("outward", 10))
ax.spines["left"].set_position(("outward", 10))
ax.spines["top"].set_color("none")
ax.spines["right"].set_color("none")
x = np.arange(1, 8, 1)
y = 2 * x + 1
ax.scatter(x, y, c="orange", s=50, edgecolors="orange")
for tickline in ax.xaxis.get_ticklines():
tickline.set_color("blue")
tickline.set_markersize(8)
tickline.set_markeredgewidth(5)
for ticklabel in ax.get_xmajorticklabels():
ticklabel.set_color("slateblue")
ticklabel.set_fontsize(12)
ticklabel.set_rotation(20)
ax.yaxis.set_major_formatter(FormatStrFormatter(f"$\yen%1.1f$"))
plt.xticks(x, day_name[0:7], rotation=20)
ax.yaxis.set_ticks_position("left")
ax.xaxis.set_ticks_position("bottom")
for tickline in ax.yaxis.get_ticklines():
tickline.set_color("lightgreen")
tickline.set_markersize(8)
tickline.set_markeredgewidth(5)
for ticklabel in ax.get_ymajorticklabels():
ticklabel.set_color("green")
ticklabel.set_fontsize(15)
ax.grid(ls=":", lw=1, color="gray", alpha=0.5)
plt.show()
4. 移动坐标轴的位置
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
mpl.rcParams['font.sans-serif'] = ['SimHei']
mpl.rcParams['font.serif'] = ['SimHei']
mpl.rcParams['axes.unicode_minus'] = False # 解决保存图像是负号'-'显示为方块的问题,或者转换负号为字符串
x = np.linspace(-2 * np.pi, 2 * np.pi, 200)
y = np.sin(x)
y1 = np.cos(x)
ax = plt.subplot(111)
ax.plot(x, y, ls="-", lw=2, label=r"$\sin(x)$")
ax.plot(x, y1, ls="-", lw=2, label=r"$\cos(x)$")
ax.legend(loc="lower left")
plt.title(r"$\sin(x)$" + "和" + r"$\cos(x)$" + "函数")
ax.set_xlim(-2 * np.pi, 2 * np.pi)
plt.xticks([-2 * np.pi, -3 * np.pi / 2, -1 * np.pi, -1 * np.pi / 2,
0, np.pi / 2, np.pi, 3 * np.pi / 2, 2 * np.pi],
[r"$-2\pi$", r"$-3\pi/2$", r"$-\pi$", r"$-\pi/2$",
r"$0$", r"$\pi/2$", r"$\pi$", r"$3\pi/3$", r"$2\pi$"]
)
ax.spines["right"].set_color("none")
ax.spines["top"].set_color("none")
ax.spines["bottom"].set_position(("data", 0))
ax.spines["left"].set_position(("data", 0))
ax.xaxis.set_ticks_position("bottom")
ax.yaxis.set_ticks_position("left")
plt.show()
ax.spines[key]
会调用轴脊字典,如bottom
、top
、right
、left
键值是对应位置轴脊,ax.spines["bottom"].set_position(("data", 0))
表示将底轴移到数轴0坐标位置
作 者:ice
个性签名:我与春风皆过客,你携秋水揽星河
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