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import numpy as np
import matplotlib.pyplot as plt
 
fig, ax = plt.subplots()
 
# 繪制一個餘弦曲線
t = np.arange(0.0, 5.0, 0.01)
s = np.cos(2*np.pi*t)
line, = ax.plot(t, s, lw=2)
 
# 繪制一個黑色，兩端縮進的箭頭
ax.annotate('local max', xy=(2, 1), xytext=(3, 1.5),
            xycoords='data',
            arrowprops=dict(facecolor='black', shrink=0.05)
            )
ax.set_ylim(-2, 2)
plt.show()

import numpy as np
import matplotlib.pyplot as plt
 
# 以步長0.005繪制一個曲線
x = np.arange(0, 10, 0.005)
y = np.exp(-x/2.) * np.sin(2*np.pi*x)
 
fig, ax = plt.subplots()
ax.plot(x, y)
ax.set_xlim(0, 10)
ax.set_ylim(-1, 1)
 
# 被注釋點的數據軸坐標和所在的像素
xdata, ydata = 5, 0
xdisplay, ydisplay = ax.transData.transform_point((xdata, ydata))
 
# 設置注釋文本的樣式和箭頭的樣式
bbox = dict(boxstyle="round", fc="0.8")
arrowprops = dict(
    arrowstyle = "->",
    connectionstyle = "angle,angleA=0,angleB=90,rad=10")
 
# 設置偏移量
offset = 72
# xycoords默認為'data'數據軸坐標，對坐標點（5,0）添加注釋
# 注釋文本參考被注釋點設置偏移量，向左2*72points，向上72points
ax.annotate('data = (%.1f, %.1f)'%(xdata, ydata),
            (xdata, ydata), xytext=(-2*offset, offset), textcoords='offset points',
            bbox=bbox, arrowprops=arrowprops)
 
# xycoords以繪圖區左下角為參考，單比特為像素
# 注釋文本參考被注釋點設置偏移量，向右0.5*72points，向下72points
disp = ax.annotate('display = (%.1f, %.1f)'%(xdisplay, ydisplay),
            (xdisplay, ydisplay), xytext=(0.5*offset, -offset),
            xycoords='figure pixels',
            textcoords='offset points',
            bbox=bbox, arrowprops=arrowprops)
 
 
plt.show()

import numpy as np
import matplotlib.pyplot as plt
 
# 繪制一個極地坐標，再以0.001為步長，畫一條螺旋曲線
fig = plt.figure()
ax = fig.add_subplot(111, polar=True)
r = np.arange(0,1,0.001)
theta = 2 * 2*np.pi * r
line, = ax.plot(theta, r, color='#ee8d18', lw=3)
 
# 對索引為800處畫一個圓點，並做注釋
ind = 800
thisr, thistheta = r[ind], theta[ind]
ax.plot([thistheta], [thisr], 'o')
ax.annotate('a polar annotation',
            xy=(thistheta, thisr),  # 被注釋點遵循極坐標系，坐標為角度和半徑
            xytext=(0.05, 0.05),    # 注釋文本放在繪圖區的0.05百分比處
            textcoords='figure fraction',
            arrowprops=dict(facecolor='black', shrink=0.05),# 箭頭線為黑色，兩端縮進5%
            horizontalalignment='left',# 注釋文本的左端和低端對齊到指定比特置
            verticalalignment='bottom',
            )
plt.show()

import matplotlib.pyplot as plt
 
# 設置繪圖區標題
fig = plt.figure()
fig.suptitle('bold figure suptitle', fontsize=14, fontweight='bold')
 
# 設置子繪圖區標題
ax = fig.add_subplot(111)
fig.subplots_adjust(top=0.85)
ax.set_title('axes title')
 
# 設置x y坐標軸的標識
ax.set_xlabel('xlabel')
ax.set_ylabel('ylabel')
 
# 紅色、透明度0.5、邊框留白10
ax.text(3, 8, 'boxed italics text in data coords', style='italic',
        bbox={
    'facecolor':'red', 'alpha':0.5, 'pad':10})
 
# 文字中有數學公式
ax.text(2, 6, r'an equation: $E=mc^2$', fontsize=15)
 
# 文字中有ASCII碼
ax.text(3, 2, 'unicode: Institut f\374r Festk\366rperphysik')
 
# 轉換坐標系
ax.text(0.95, 0.01, 'colored text in axes coords',
        verticalalignment='bottom', horizontalalignment='right',
        transform=ax.transAxes,
        color='green', fontsize=15)
 
# 在2,1處畫個圓點，添加注釋
ax.plot([2], [1], 'o')
ax.annotate('annotate', xy=(2, 1), xytext=(3, 4),
            arrowprops=dict(facecolor='black', shrink=0.05))
 
ax.axis([0, 10, 0, 10])
 
plt.show()