matplotlib直方图

直方图：

用于绘制连续的数据
和前面几种绘图最大的区别就是，绘图使用plt.hist(原始数据a，组数[，density=True])函数，并且简单绘图时不需要传x、y轴座标，只需要传进待绘图的原始连续数据，设置好分组数量，函数会自动将每组数据的个数计算出来，并且绘制到图上。如果使用density=True,则y轴座标则会由数量变为频率。
其余的绘制过程和折线图使用函数一样

连续数据绘制直方图时：

from matplotlib import pyplot as plt
import matplotlib
import random


#设置中文字体
font = {'family': 'STKAITI',
        'weight': 'bold',
        'size': '10'}

matplotlib.rc("font", **font)



#直方图座标
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]


#print(min(a), max(a), -min(a)+max(a))
#计算组数
d = 3
l = max(a)-min(a)
num_bins = l//d

#图片大小
plt.figure(figsize=(8, 4), dpi=100)

#设置x、y轴座标对应的值
x_label = list(range(min(a), max(a)+d, d))
plt.xticks(x_label)


##绘图：
plt.hist(tuple(a), num_bins, density=True)
plt.grid(alpha=0.3)
plt.show()

如果原始数据经过初步整理，组织成不连续的数据，想要仍然达到直方图的目的，则使用条形图绘制，达到与直方图相似的效果

‘’’
在美国2004年人口普查发现有124 million的人在离家相对较远的地方工作。根据他们从家到上班地点所需要的时间,通过抽样统计(最后一列)出了下表的数据,这些数据能够绘制成直方图么?
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]
‘’’

#设置中文字体
font = {'family': 'STKAITI',
        'weight': 'bold',
        'size': '10'}

matplotlib.rc("font", **font)


interval = [0,5,10,15,20,25,30,35,40,45,60,90, 150]
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]

print(len(interval), len(width), len(quantity))


#得到x、y轴座标
x = list(range(1, len(quantity)+1))
y = quantity


#绘制x、y轴座标刻度
x_id = [i-0.5 for i in range(1, 14)]
plt.xticks(x_id, interval)
y_id = list(range(250, 4250, 250))
plt.yticks(y_id)

#绘图
plt.bar(x, y, width=1)
plt.grid(alpha=0.3)
plt.show()