matplotlib基础（3）之柱状图bar

悠悠 2022-09-04 10:58 172阅读 0赞

from matplotlib import colors
    import matplotlib.pyplot as plt
    import numpy as np
    from numpy.core.fromnumeric import size
    import pandas as pd
    
    # 柱状图 bar x,y：float or array-like
    x = ['Q1', 'Q2', 'Q3', 'Q4', ]
    y = [10, 32, 21, 18]
    rect = plt.bar(x, y, width=0.3)
    plt.grid(True)  # 网格
    
    
    # 绘制标度值   enumerate得到索引值
    # print(index, item)
    """ 
        0 Rectangle(xy=(-0.15, 0), width=0.3, height=10, angle=0)
        1 Rectangle(xy=(0.85, 0), width=0.3, height=32, angle=0)
        2 Rectangle(xy=(1.85, 0), width=0.3, height=21, angle=0)
        3 Rectangle(xy=(2.85, 0), width=0.3, height=18, angle=0)
    """
    
    for index, item in enumerate(rect):  # index:索引   item:圆柱对象
        _x = item.get_x()
        _y = item.get_height()
        plt.text(_x, _y, y[index])  # y[index] == _y
    plt.ylim(0, 40)  # 单独修改y轴 刻度值
    plt.show()
    
    
    #横线柱形图
    data2 = pd.DataFrame(np.random.rand(10,4),columns=['A','B','C','D'])
    print(data2)
    """
    注意： 这里pandas数据 可以直接使用绘图
    """
    data2.plot(kind="barh")  
    plt.show()
    
    """
    将图形存起来  savefig
    """
    data2.plot(kind="barh",stacked=True) #堆叠起来的圆柱图
    plt.savefig('./plt.png')
    plt.show()

效果图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nhb3lhbjA4Mjk_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nhb3lhbjA4Mjk_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nhb3lhbjA4Mjk_size_16_color_FFFFFF_t_70 2][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nhb3lhbjA4Mjk_size_16_color_FFFFFF_t_70]: /images/20220829/8620a56e852e49da877538dd6faf1512.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nhb3lhbjA4Mjk_size_16_color_FFFFFF_t_70 1]: /images/20220829/e10fd05dd6454d5da24cf9c091bb5989.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nhb3lhbjA4Mjk_size_16_color_FFFFFF_t_70 2]: /images/20220829/c0e703e31e1746548a0275177643be7f.png