Python 从字典中绘制直方图
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Plot a histogram from a Dictionary
提问by Matteo
I created a dictionarythat counts the occurrences in a listof every key and I would now like to plot the histogram of its content.
我创建了一个dictionary计算list每个键a中出现的次数，现在我想绘制其内容的直方图。
This is the content of the dictionary I want to plot:
这是我要绘制的字典的内容：
{1: 27, 34: 1, 3: 72, 4: 62, 5: 33, 6: 36, 7: 20, 8: 12, 9: 9, 10: 6, 11: 5, 12: 8, 2: 74, 14: 4, 15: 3, 16: 1, 17: 1, 18: 1, 19: 1, 21: 1, 27: 2}
So far I wrote this:
到目前为止，我写了这个：
import numpy as np
import matplotlib.pyplot as plt
pos = np.arange(len(myDictionary.keys()))
width = 1.0 # gives histogram aspect to the bar diagram
ax = plt.axes()
ax.set_xticks(pos + (width / 2))
ax.set_xticklabels(myDictionary.keys())
plt.bar(myDictionary.keys(), ******, width, color='g')
# ^^^^^^ what should I put here?
plt.show()
I tried by simply doing
我试着简单地做
plt.bar(myDictionary.keys(), myDictionary, width, color='g')
but this is the result:
但这是结果：
and I don't know why the 3 bars are shifted and also I'd like the histogram to be displayed in a ordered fashion.
我不知道为什么 3 个条形图会移动，而且我希望直方图以有序的方式显示。
Can somebody tell me how to do it?
有人能告诉我怎么做吗？
采纳答案by Alvaro Fuentes
You can use the function for plotting histograms like this:
您可以使用该函数绘制直方图，如下所示：
a = np.random.random_integers(0,10,20) #example list of values
plt.hist(a)
plt.show()
Or you can use myDictionaryjust like this:
或者你可以myDictionary像这样使用：
plt.bar(myDictionary.keys(), myDictionary.values(), width, color='g')
回答by mcsilvio
values = [] #in same order as traversing keys
keys = [] #also needed to preserve order
for key in myDictionary.keys():
keys.append(key)
values.append(myDictionary[key])
Use 'keys' and 'values'. This ensures that the order is preserved.
使用“键”和“值”。这可确保保留订单。
回答by Franck Dernoncourt
With Python 3 you need to use list(your_dict.keys())instead of your_dict.keys()(otherwise you get TypeError: 'dict_keys' object does not support indexing):
使用 Python 3 你需要使用list(your_dict.keys())而不是your_dict.keys()（否则你会得到TypeError: 'dict_keys' object does not support indexing）：
import matplotlib.pyplot as plt
dictionary = {1: 27, 34: 1, 3: 72, 4: 62, 5: 33, 6: 36, 7: 20, 8: 12, 9: 9, 10: 6, 11: 5,
12: 8, 2: 74, 14: 4, 15: 3, 16: 1, 17: 1, 18: 1, 19: 1, 21: 1, 27: 2}
plt.bar(list(dictionary.keys()), dictionary.values(), color='g')
plt.show()
Tested with Matplotlib 2.0.0 and python 3.5.
使用 Matplotlib 2.0.0 和 python 3.5 进行测试。
FYI: Plotting a python dict in order of key values
仅供参考：按键值的顺序绘制python dict
回答by organicData
In case the keys of the myDictionaryare not uniformed distributed, its helpful to use the keys as str:
如果密钥myDictionary不是统一分布的，将密钥用作str：
plt.bar([ str(i) for i in myDictionary.keys()], myDictionary.values(), color='g')
