matplotlib

实例一：

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-3, 3, 50)
y1 = x ** 2
y2 = 2 * x + 1
plt.figure(num=1, figsize=(8, 5))

plt.xlim((-1, 2))
plt.ylim((-2, 3))
plt.xlabel('I am x')
plt.ylabel('I am y')
new_ticks = np.linspace(-1, 2, 5)
print(new_ticks)
plt.xticks(new_ticks)
plt.yticks([-1, 2], ['really good', 'good'])
ax = plt.gca()
ax.spines['right'].set_color('none')
ax.spines['top'].set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')
ax.spines['bottom'].set_position(('data', 0))
ax.spines['left'].set_position(('data', 0))
l1, = plt.plot(x, y1, label='up')
l2, = plt.plot(x, y2, color='red', linewidth=1.0, linestyle='--', label='down')
plt.legend(handles=[l1, l2], labels=['aaa', 'bbb'], loc='best')

x0 = 0
y0 = 2 * x0 + 1
plt.scatter(x0, y0, s=50, color='b')
plt.plot([x0, x0], [0, y0], 'k--', lw=2.5)
plt.annotate(r'$2x+1=%s$' % y0, xy=(x0, y0), xycoords='data', xytext=(+30, -30), textcoords='offset points',
             fontsize=16, arrowprops=dict(arrowstyle='->', connectionstyle='arc3, rad=.2'))
plt.text(-1, 1, r'$This is the some text.$', fontdict={'size': 12, 'color': 'r'})
for label in ax.get_xticklabels() + ax.get_yticklabels():
    label.set_fontsize(12)
    label.set_bbox(dict(facecolor='white', edgecolor='none', alpha=0.7))

plt.show()

实例二：

import matplotlib.pyplot as plt
import numpy as np

n = 1024
X = np.random.normal(0, 1, n)
Y = np.random.normal(0, 1, n)
T = np.arctan2(Y, X)
plt.scatter(X, Y, s=10, c=T, alpha=0.5)
plt.xlim((-1.5, 1.5))
plt.ylim((-1.5, 1.5))
plt.xticks(())
plt.yticks(())
plt.show()

 实例三：

import matplotlib.pyplot as plt
import numpy as np

n = 12
X = np.arange(n)
Y1 = (1 - X / float(n)) * np.random.uniform(0.5, 1.0, n)
Y2 = (1 - X / float(n)) * np.random.uniform(0.5, 1.0, n)

plt.bar(X, +Y1, facecolor='#9999ff', edgecolor='white')
plt.bar(X, -Y2, facecolor='#ff9999', edgecolor='white')
for x, y in zip(X, Y1):
    plt.text(x + 0.1, y + 0.05, '%.2f' % y, ha='center', va='bottom')
for x, y in zip(X, Y2):
    plt.text(x + 0.1, -y - 0.05, '%.2f' % -y, ha='center', va='top')
plt.xlim(-0.5, n)
plt.xticks(())
plt.ylim(-1.25, 1.25)
plt.yticks(())
plt.show()

 实例四：

import matplotlib.pyplot as plt
import numpy as np


def f(x, y):
    # the height function
    return (1 - x / 2 + x ** 5 + y ** 3) * np.exp(-x ** 2, - y ** 2)


n = 256
x = np.linspace(-3, 3, n)
y = np.linspace(-3, 3, n)
X, Y = np.meshgrid(x, y)
plt.contourf(X, Y, f(X, Y), 8, alpha=0.5, cmap=plt.cm.hot)
C = plt.contour(X, Y, f(X, Y), 8, colors='black', linewidth=0.5)
plt.clabel(C, inline=True, fontsize=10)
plt.xticks(())
plt.yticks(())
plt.show()