from pylab import * 
from matplotlib.ticker import MultipleLocator, FormatStrFormatter 
xmajorLocator  = MultipleLocator(20) #將x主刻度標簽設置為20的倍數 
xmajorFormatter = FormatStrFormatter('%1.1f') #設置x軸標簽文本的格式 
xminorLocator  = MultipleLocator(5) #將x軸次刻度標簽設置為5的倍數 
ymajorLocator  = MultipleLocator(0.5) #將y軸主刻度標簽設置為0.5的倍數 
ymajorFormatter = FormatStrFormatter('%1.1f') #設置y軸標簽文本的格式 
yminorLocator  = MultipleLocator(0.1) #將此y軸次刻度標簽設置為0.1的倍數 
t = arange(0.0, 100.0, 1) 
s = sin(0.1*pi*t)*exp(-t*0.01) 
ax = subplot(111) #注意:一般都在ax中設置,不再plot中設置 
plot(t,s,'--b*') 
#設置主刻度標簽的位置,標簽文本的格式 
ax.xaxis.set_major_locator(xmajorLocator) 
ax.xaxis.set_major_formatter(xmajorFormatter) 
ax.yaxis.set_major_locator(ymajorLocator) 
ax.yaxis.set_major_formatter(ymajorFormatter) 
#顯示次刻度標簽的位置,沒有標簽文本 
ax.xaxis.set_minor_locator(xminorLocator) 
ax.yaxis.set_minor_locator(yminorLocator) 
ax.xaxis.grid(True, which='major') #x坐標軸的網格使用主刻度 
ax.yaxis.grid(True, which='minor') #y坐標軸的網格使用次刻度 
 
show()

import matplotlib.pyplot as plt 
help(plt.xticks) 

import numpy as np 
import matplotlib.pyplot as plt 
fig,ax = plt.subplots() 
x = [1,2,3,4,5] 
y = [0,2,5,9,15] 
#ax is the axes instance 
group_labels = ['a', 'b','c','d','e'] 
plt.plot(x,y) 
plt.xticks(x, group_labels, rotation=0) 
plt.grid() 
plt.show() 

import matplotlib.pyplot as pl 
import numpy as np 
from matplotlib.ticker import MultipleLocator, FuncFormatter 
x = np.arange(0, 4*np.pi, 0.01) 
y = np.sin(x) 
pl.figure(figsize=(10,6)) 
pl.plot(x, y,label="$sin(x)$") 
ax = pl.gca() 
 
def pi_formatter(x, pos): 
  """ 
  比較羅嗦地將數值轉換為以pi/4為單位的刻度文本 
  """ 
  m = np.round(x / (np.pi/4)) 
  n = 4 
  if m%2==0: m, n = m/2, n/2 
  if m%2==0: m, n = m/2, n/2 
  if m == 0: 
    return "0" 
  if m == 1 and n == 1: 
    return "$\pi$" 
  if n == 1: 
    return r"$%d \pi$" % m 
  if m == 1: 
    return r"$\frac{\pi}{%d}$" % n 
  return r"$\frac{%d \pi}{%d}$" % (m,n) 
 
# 設置兩個坐標軸的范圍 
pl.ylim(-1.5,1.5) 
pl.xlim(0, np.max(x)) 
 
# 設置圖的底邊距 
pl.subplots_adjust(bottom = 0.15) 
 
pl.grid() #開啟網格 
 
# 主刻度為pi/4 
ax.xaxis.set_major_locator( MultipleLocator(np.pi/4) ) 
 
# 主刻度文本用pi_formatter函數計算 
ax.xaxis.set_major_formatter( FuncFormatter( pi_formatter ) ) 
 
# 副刻度為pi/20 
ax.xaxis.set_minor_locator( MultipleLocator(np.pi/20) ) 
 
# 設置刻度文本的大小 
for tick in ax.xaxis.get_major_ticks(): 
  tick.label1.set_fontsize(16) 
 
pl.legend() 
pl.show()