python+matplotlib练习

基础环境：
1.python34
2.matplotlib1.4.3
3.win32

matplotlib基础练习一 plot()

import matplotlib.pyplot as plt
plt.plot([1,2,3,4])
plt.ylabel('some numbers')
plt.show()

效果

如上：若只赋予plot()一个参数，那么matplotlib会自动赋值给x轴，且从0开始，所以该图效果等同于：

plt.plot([0,1,2,3],[1,2,3,4])

例子：

plt.plot([0,1,2,3],[1,2,3,4],color='#254424',linestyle='dashed',label='line 1')
plt.plot([1,2,3],[1,4,9],'rs',label='line 2')

更多使用方法要查看帮助 ： help(“matplotlib.pyplot.plot”)

---

matplotlib基础练习二 文字
在图标上增加文字，主要使用如下函数

1. text() - add text at an arbitrary location to the Axes;matplotlib.axes.Axes.text() in the API.
2. xlabel() - add an axis label to the x-axis;matplotlib.axes.Axes.set_xlabel() in the API.
3. ylabel() - add an axis label to the y-axis;matplotlib.axes.Axes.set_ylabel() in the API.
4. title() - add a title to the Axes; matplotlib.axes.Axes.set_title() in the API.
5. figtext() - add text at an arbitrary location to the Figure; matplotlib.figure.Figure.text() in the API.
6. suptitle() - add a title to the Figure; matplotlib.figure.Figure.suptitle() in the API.
7. annotate() - add an annotation, with
   optional arrow, to the Axes ; matplotlib.axes.Axes.annotate() in the API.

例：

# -*- coding: utf-8 -*-
import matplotlib.pyplot as plt

fig = plt.figure()
fig.suptitle('bold figure suptitle', fontsize=14, fontweight='bold')

ax = fig.add_subplot(111)
fig.subplots_adjust(top=0.85)
ax.set_title('axes title')

ax.set_xlabel('xlabel')
ax.set_ylabel('ylabel')

ax.text(3, 8, 'boxed italics text in data coords', style='italic',
        bbox={'facecolor':'red', 'alpha':0.5, 'pad':10})

ax.text(2, 6, r'an equation: $E=mc^2$', fontsize=15)

ax.text(0.95, 0.01, 'colored text in axes coords',
        verticalalignment='bottom', horizontalalignment='right',
        transform=ax.transAxes,
        color='green', fontsize=15)


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()

效果如图：

---

matplotlib基础练习三 基本饼图

import matplotlib.pyplot as plt

labels = 'GreenApple', 'YellowApple', 'RedApple'
sizes = [40, 25, 35]
colors = ['yellowgreen', 'gold', '#ff2121',]
explode = (0, 0.1, 0) 


plt.pie(sizes, explode=explode, labels=labels, colors=colors,
        autopct='%1.1f%%', shadow=True, startangle=90)

plt.axis('equal')

plt.show()

效果：

---

matplotlib基础练习四-以时间为轴的图表

目录结构： -date_demo.py -aaa

-aapl.csv

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab
import matplotlib.ticker as ticker

r = mlab.csv2rec('aaa/aapl.csv')
r.sort()
r = r[-30:]  # get the last 30 days

N = len(r)
ind = np.arange(N)  # the evenly spaced plot indices

def format_date(x, pos=None):
    thisind = np.clip(int(x+0.5), 0, N-1)
    return r.date[thisind].strftime('%Y-%m-%d')

fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(ind, r.adj_close, 'o-')
ax.xaxis.set_major_formatter(ticker.FuncFormatter(format_date))
fig.autofmt_xdate()

plt.show()

aapl.csv下载地址

---

matplotlib在线教程