Python - Matplotlib多直方图

Question

我想绘制几个直方图，但有时候的箱子比其他箱子大。我无法解释为什么我会得到这个...你可以在下面看到一个情节，红色的箱子比其他箱子宽。我的代码显示在图下面

import matplotlib as mpl
font = {'family':'serif','serif':'serif','weight':'normal','size':'18'}
mpl.rc('font',**font)
mpl.rc('text',usetex=True)

plt.close()
plt.subplots_adjust(left=0.15, bottom=0.15)
num_bins = 50

n, bins, patches = plt.hist(A, num_bins, facecolor='blue', alpha=0.5, label='Healthy SG')

n, bins, patches = plt.hist(B, num_bins, facecolor='red', alpha=0.5, label='Aged SG')

n, bins, patches = plt.hist(C, num_bins, facecolor='yellow', alpha=0.5, label='Healthy VG')

n, bins, patches = plt.hist(D, num_bins, facecolor='green', alpha=0.5, label='Aged VG')

plt.ylim(0.,10.)
plt.tick_params(axis='both', which='major', labelsize=14)
plt.grid(True)
plt.legend(loc=2, fontsize= 16)

plt.show()

Answer 1

当您使用bins=num_bins时，每次调用plt.hist都会决定bin边缘应该独立的位置。每次调用都会尝试选择适合传递数据的bin边。随着数据的变化，bin边缘也会发生变化。

要使bin宽度保持不变，您需要为每次调用plt.hist传递相同的显式bin边缘数组：

num_bins = 50
data = np.concatenate([A,B,C,D])
min_data, max_data = data.min(), data.max()
bins = np.linspace(min_data, max_data, num_bins)
plt.hist(A, bins=bins, facecolor='blue', alpha=0.5, label='Healthy SG')
plt.hist(B, bins=bins, facecolor='red', alpha=0.5, label='Aged SG')
plt.hist(C, bins=bins, facecolor='yellow', alpha=0.5, label='Healthy VG')
plt.hist(D, bins=bins, facecolor='green', alpha=0.5, label='Aged VG')