在Python中，从一个大的、单个的数据集中创建多个直方图，按用户分组

我有一个大数据集，df:

  User              duration

  amy                582         
  amy                27
  amy                592
  amy                16
  amy                250
  tom                33
  tom                10
  tom                40
  tom                100

我想按用户分组，然后为每个用户创建直方图：

 amy (histogram image)


 tom (histogram image)

以下是dput：

structure(list(User = structure(c(1L, 1L, 1L, 1L, 1L, 2L, 2L, 
2L, 2L), .Label = c("amy", "tom"), class = "factor"), duration = c(582L, 
27L, 592L, 16L, 250L, 33L, 10L, 40L, 100L)), class = "data.frame", row.names = c(NA, 
-9L))

我知道如何使用以下代码在Python中创建直方图：，但如何在Python中创建多个直方图，并按用户分组。我应该编一本字典吗

 import numpy as np
 import matplotlib.mlab as mlab
 import matplotlib.pyplot as plt

 df = (amy[582,27, 592, 16, 250], tom[33,10,40,100])
 num_bins = 20
 n, bins, patches = plt.hist(x, num_bins, facecolor='blue', alpha=0.5)
 plt.show()

如有任何建议，我们将不胜感激

df = pd.DataFrame({'user':['amy', 'amy','amy','amy','amy', 'tom', 'tom', 'tom','tom',],
              'duration': [582, 27, 592, 16, 250, 33, 10, 40, 100]})

ax = df['duration'].hist(by=df['user'])

for a in ax.flatten():
    a.set_xlabel("duration")
    a.set_ylabel("frequency")

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让我试试。非常感谢。