使用 pandas 自定义排序 [英] Custom sorting with Pandas

问题描述

我有以下数据框，我想先按重要性"排序，然后再按名称"排序:

I have the following dataframe that I would like to sort first by Criticality and then by Name:

Name        Criticality
baz         High
foo         Critical
baz         Low
foo         Medium
bar         High
bar         Low
bar         Medium
...

我一直试图使用这篇文章中提供的答案来做到这一点.但我无法正常工作.

I've been trying to do this using the answer provided in this post but I just can't get it to work.

最终结果应该是这样

Name        Criticality
bar         High
bar         Medium
bar         Low
baz         High
baz         Low
foo         Critical
foo         Medium

推荐答案

一种方法是使用自定义字典来创建排名"列，然后使用进行排序，然后在排序后删除该列:

One approach would be to use a custom dict to create a 'rank' column, we then use to sort with and then drop the column after sorting:

In [17]:
custom_dict = {'Critical':0, 'High':1, 'Medium':2, 'Low':3}  
df['rank'] = df['Criticality'].map(custom_dict)
df

Out[17]:

  Name Criticality  rank
0  baz        High     1
1  foo    Critical     0
2  baz         Low     3
3  foo      Medium     2
4  bar        High     1
5  bar         Low     3
6  bar      Medium     2

[7 rows x 3 columns]

In [19]:
# now sort by 'Name' and 'rank', it will first sort by 'Name' column first and then 'rank'
df.sort(columns=['Name', 'rank'],inplace=True)
df

Out[19]:

  Name Criticality  rank
4  bar        High     1
6  bar      Medium     2
5  bar         Low     3
0  baz        High     1
2  baz         Low     3
1  foo    Critical     0
3  foo      Medium     2

[7 rows x 3 columns]

In [21]:
# now drop the 'rank' column
df.drop(labels=['rank'],axis=1)

Out[21]:

  Name Criticality
4  bar        High
6  bar      Medium
5  bar         Low
0  baz        High
2  baz         Low
1  foo    Critical
3  foo      Medium

[7 rows x 2 columns]

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