列名称在熊猫中的异常排序

Question

当我将数据框从熊猫导出到Excel电子表格时，我的列顺序如下所示，其中“ 10个最大事件”被认为是“ 1个最大事件”之后的第二个，而不是“ 2个最大事件”。 我希望它以数字顺序显示。 即“ 1个最大事件”，“ 2个最大事件”，“ 10个最大事件”

ID_1    Permit No.        ID_2       1 Largest Event    10 Largest Event    2 Largest Event
10220   To Be Permitted 0010001-24.1       4.0548                  0.822    3.9611

为什么会这样呢？ 这是一个较小的格式化错误，但可能会让人感到非常讨厌。

Answer 1

从natsort reindex

from natsort import natsorted
l=['1 Largest Event','10 Largest Event','2 Largest Event']
natsorted(l)
Out[789]: ['1 Largest Event', '2 Largest Event', '10 Largest Event']
df=df.reindex(columns=natsorted(list(df)))

Answer 2

问题是您的列按字典顺序像字符串一样排序。

因此需要使用自定义函数进行排序，方法是先将拆分值转换为int ：

df = df[sorted(df.columns, key=lambda x: int(x.split()[0]))]

样品 ：

cols = ['1 Largest Event', 
        '10 Largest Event', 
        '2 Largest Event',
        '3 Largest Event',
        '4 Largest Event',
        '5 Largest Event', 
        '6 Largest Event', 
        '7 Largest Event', 
        '8 Largest Event', 
        '9 Largest Event']

df = pd.DataFrame(0, columns=cols, index=[0])
print (df)
   1 Largest Event  10 Largest Event  2 Largest Event  3 Largest Event  \
0                0                 0                0                0   

   4 Largest Event  5 Largest Event  6 Largest Event  7 Largest Event  \
0                0                0                0                0   

   8 Largest Event  9 Largest Event  

df = df[sorted(df.columns, key=lambda x: int(x.split()[0]))]
print (df)

   1 Largest Event  2 Largest Event  3 Largest Event  4 Largest Event  \
0                0                0                0                0   

   5 Largest Event  6 Largest Event  7 Largest Event  8 Largest Event  \
0                0                0                0                0   

   9 Largest Event  10 Largest Event  
0                0                 0  

编辑：

您还可以过滤最后3列进行排序：

df = df[df.columns[:3].tolist() + sorted(df.columns[3:], key=lambda x: int(x.split()[0]))]
print (df)
    ID_1       Permit No.          ID_2  1 Largest Event  2 Largest Event  \
0  10220  To Be Permitted  0010001-24.1           4.0548           3.9611   

   10 Largest Event  
0             0.822