使用Matplotlib畫對數函數

#coding:utf-8

import matplotlib.pyplot as plt
import numpy as np
from numpy.lib.scimath import logn
from math import e
import matplotlib as mpl
#防止中文亂碼問題
mpl.rcParams['font.sans-serif']=[u'SimHei']
mpl.rcParams['axes.unicode_minus']=False

x=np.linspace(0,6,100)  #創建100個0到6之間的等比數列

plt.plot(x,np.log(x)/np.log(0.5),'y-', linewidth=2, label=u'log0.5(x)')#log0.5(x)
plt.plot(x,logn(e,x),'b-',linewidth=2, label=u'loge(x)')#loge(x)
#plt.plot(x,np.log(x)/np.log(5))
plt.plot(x,logn(5,x),'g-',linewidth=2, label=u'loge(x)') #等於求log5(X)
plt.plot(x,np.log10(x),'r-',linewidth=2, label=u'loge(x)')#log10(x)

plt.axis([0, 2.5, -3., 5.])#指定畫圖板的長寬
plt.legend(loc = 'lower right') #圖例的位置
plt.grid(True)#需要網格
plt.show()