.sort_values()方法对DataFrame数据帧进行排序

和sort_index()方法不一样的是，sort_values()方法可以指定排序是根据哪一列的内容，当然，我们需要在括号中填写那一列的参数，用by作为参数关键词传入。比如我们按照分数（score）降序排列，就可以编写以下程序：

import pandas as pd
dict_data = {
	'score'	:[95,98,92,89,82,93],
	'gender':['M','F','M',"M","F","M"]
}
DF_data = pd.DataFrame(dict_data,
	columns=['gender','hometown','score'],
	index=["Li Lei","Han Meimei","Tom","Adam","Betty","Curry"])

DF_data = DF_data.fillna({'hometown':'unknown'})
print(DF_data.sort_values(by = 'score', ascending = False))

我们将得到以下输出结果：

           gender hometown  score
Han Meimei      F  unknown     98
Li Lei          M  unknown     95
Curry           M  unknown     93
Tom             M  unknown     92
Adam            M  unknown     89
Betty           F  unknown     82
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