使用python中的Matplotlib绘图示例

清疚 2022-08-05 15:30 246阅读 0赞

当我们按照前一篇博文

[http://blog.csdn.net/tao\_627/article/details/44004541][http_blog.csdn.net_tao_627_article_details_44004541]

配置好python的绘图环境后,下面给出几个有代表性的例子:

一.绘制柱状图

#!/usr/bin/env_python
    #encoding: utf-8
    
    import matplotlib.pyplot as plt
    
    def bar_chart_generator():
        l=[1,2,3,4,5]
        h=[20,14,38,27,9]
        w=[0.1,0.2,0.3,0.4,0.5]
        b=[1,2,3,4,5]
        fig=plt.figure()
        ax=fig.add_subplot(111)
        rects=ax.bar(l,h,w,b)
        plt.show()
    
    bar_chart_generator()

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二.绘制曲线图

#!/usr/bin/env_python
    #encoding: utf-8
    #usage: python curve_demo.py
    
    import matplotlib.pyplot as plt
    import numpy as np
    
    #To draw y=x^2(-3<=x<=3)
    
    x = np.arange(-3,3.5,0.5)
    y = [ele**2 for ele in x]
    z = [ele *2 for ele in x]
    
    fig = plt.figure(1)
    
    ax = fig.add_subplot(211)
    line1 = ax.plot(x,y,'ro-')
    
    ax = fig.add_subplot(212)
    line2 = ax.plot(x,z,'g-')
    
    plt.show()

![Center 1][]

三.绘制折线图

#!/usr/bin/env_python
    #encoding: utf-8
    
    import numpy as np
    import pylab as pl
    from StringIO import StringIO
    
    data_str = """
    
    2012-04-01_02 68
    
    2012-04-01_05 70
    
    2012-04-01_08 69
    
    2012-04-01_11 71
    
    2012-04-01_14 72
    
    2012-04-01_20 70
    
    2012-04-02_02 71
    
    2012-04-02_05 70
    
    2012-04-02_08 69
    
    2012-04-02_11 71
    
    2012-04-02_14 69
    
    2012-04-02_20 71
    
    2012-04-03_02 74
    
    2012-04-03_05 73
    
    2012-04-03_08 77
    
    2012-04-03_11 70
    
    2012-04-03_14 71
    
    2012-04-03_20 70
    
    2012-04-04_02 70
    
    2012-04-04_05 72
    
    2012-04-04_08 72
    
    2012-04-04_11 69
    
    2012-04-04_14 71
    
    2012-04-04_20 69
    
    2012-04-05_02 75
    
    """
    
    data = np.loadtxt(StringIO(data_str), dtype=np.dtype([("t", "S13"),("v", float)]))
    
    datestr = np.char.replace(data["t"], "_", " ")
    
    t = pl.datestr2num(datestr)
    
    v = data["v"]
    
    pl.plot_date(t, v, fmt="-o")
    
    pl.subplots_adjust(bottom=0.3)
    
    ax = pl.gca()
    ax.fmt_xdata = pl.DateFormatter('%Y-%m-%d %H:%M:%S')
    
    pl.xticks(rotation=90)
    pl.xticks(t, datestr) # 如果以数据点为刻度，则注释掉这一行
    
    ax.xaxis.set_major_formatter(pl.DateFormatter('%Y-%m-%d %H'))
    
    pl.grid()
    pl.show()

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参考文献

\[1\].http://blog.sina.com.cn/s/blog\_68b606350101ryao.html

[http_blog.csdn.net_tao_627_article_details_44004541]: http://blog.csdn.net/tao_627/article/details/44004541
[Center]: /images/20220805/6027ebb355f149348590e89fb6251e4e.png
[Center 1]: https://img-blog.csdn.net/20150301221418046?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdGFvXzYyNw==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 2]: https://img-blog.csdn.net/20150301221529178?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdGFvXzYyNw==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center