matplotlib直方圖

直方圖：

用於繪製連續的數據
和前面幾種繪圖最大的區別就是，繪圖使用plt.hist(原始數據a，組數[，density=True])函數，並且簡單繪圖時不需要傳x、y軸座標，只需要傳進待繪圖的原始連續數據，設置好分組數量，函數會自動將每組數據的個數計算出來，並且繪製到圖上。如果使用density=True,則y軸座標則會由數量變爲頻率。
其餘的繪製過程和折線圖使用函數一樣

連續數據繪製直方圖時：

from matplotlib import pyplot as plt
import matplotlib
import random


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

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



#直方圖座標
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))
#計算組數
d = 3
l = max(a)-min(a)
num_bins = l//d

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

#設置x、y軸座標對應的值
x_label = list(range(min(a), max(a)+d, d))
plt.xticks(x_label)


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

如果原始數據經過初步整理，組織成不連續的數據，想要仍然達到直方圖的目的，則使用條形圖繪製，達到與直方圖相似的效果

‘’’
在美國2004年人口普查發現有124 million的人在離家相對較遠的地方工作。根據他們從家到上班地點所需要的時間,通過抽樣統計(最後一列)出了下表的數據,這些數據能夠繪製成直方圖麼?
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]
‘’’

#設置中文字體
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軸座標
x = list(range(1, len(quantity)+1))
y = quantity


#繪製x、y軸座標刻度
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)

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