matplotlib——直方图（python）-编程知识

matplotlib——直方图（python）

需求

假设你获取了250部电影的时长，希望统计出这些电影时长的分布状态等信息。

代码

from matplotlib import pyplot as plt
import matplotlibmatplotlib.rc("font",family="FangSong")# 初始化数据
a=[131,  98, 125, 131, 124, 139, 131, 117, 128, 108, 135, 138, 131, 102, 107, 114, 119, 128, 121, 142, 127, 130, 124, 101, 110, 116, 117, 110, 128,128, 115,  99, 136, 126, 134,  95, 138, 117, 111,78, 132, 124, 113, 150, 110, 117,  86,  95, 144, 105, 126, 130,126, 130, 126, 116, 123, 106, 112, 138, 123,  86, 101,  99, 136,123, 117, 119, 105, 137, 123, 128, 125, 104, 109, 134, 125, 127,105, 120, 107, 129, 116, 108, 132, 103, 136, 118, 102, 120, 114,105, 115, 132, 145, 119, 121, 112, 139, 125, 138, 109, 132, 134,156, 106, 117, 127, 144, 139, 139, 119, 140,  83, 110, 102,123,107, 143, 115, 136, 118, 139, 123, 112, 118, 125, 109, 119, 133,112, 114, 122, 109, 106, 123, 116, 131, 127, 115, 118, 112, 135,115, 146, 137, 116, 103, 144,  83, 123, 111, 110, 111, 100, 154,136, 100, 118, 119, 133, 134, 106, 129, 126, 110, 111, 109, 141,120, 117, 106, 149, 122, 122, 110, 118, 127, 121, 114, 125, 126,114,140, 103, 130, 141, 117, 106, 114, 121, 114, 133, 137,  92,121, 112, 146,  97, 137, 105,  98, 117, 112,  81,  97, 139, 113,134, 106, 144, 110, 137, 137, 111,104, 117, 100, 111, 101, 110,105, 129, 137, 112, 120, 113, 133, 112,  83,  94, 146, 133, 101,131, 116, 111,  84, 137, 115, 122, 106, 144, 109, 123, 116, 111,111, 133, 150]plt.figure(figsize=(20,8),dpi=200)# 设置组距/组数
d=3
num=(max(a)-min(a))//d#设置x轴的刻度
plt.xticks(range(min(a),max(a)+d,d))# 绘制直方图
plt.hist(a,num)
plt.grid()# 展示
plt.show()

效果

在这里插入图片描述

说明

直方图重难点是设置组数，我们一般按照公式 $\over 组距}$ 。我们使用plt.hist传入两个参数，第一个是数据样本，第二个就是组数。

拓展

需求

在这里插入图片描述

代码

from matplotlib import pyplot as plt
import matplotlibmatplotlib.rc("font",family="FangSong")# 初始化数据
interval = [0,5,10,15,20,25,30,35,40,45,60,90]
width = [5,5,5,5,5,5,5,5,5,15,30,60]
quantity = [836,2737,3723,3926,3596,1438,3273,642,824,613,215,47]#设置图形大小
plt.figure(figsize=(20,8),dpi=80)plt.bar(range(12),quantity,width=1)#设置x轴的刻度
_x = [i-0.5 for i in range(13)]
_xtick_labels =  interval+[150]
plt.xticks(_x,_xtick_labels)plt.grid(alpha=0.4)
plt.show()