Question

我正在尝试将数据附加到日志中，其中列的顺序不是按字母顺序排列，但具有逻辑意义，例如

Org_Goals_1  Calc_Goals_1  Diff_Goals_1   Org_Goals_2 Calc_Goals_2 Diff_Goals_2

我正在基于不同变量进行多次计算，并通过在每次运行后附加值的字典来记录结果。有没有办法阻止df.append（）函数按字母顺序排列？

Answer 1

实际上，我发现了＃34;高级索引＆＃34;工作得很好

df2=df.ix[:,'order of columns']

Answer 2

似乎你必须在追加操作后重新排序列：

In [25]:
# assign the appended dfs to merged
merged = df1.append(df2)
# create a list of the columns in the order you desire
cols = list(df1) + list(df2)
# assign directly
merged.columns = cols
# column order is now as desired
merged.columns
Out[25]:
Index(['Org_Goals_1', 'Calc_Goals_1', 'Diff_Goals_1', 'Org_Goals_2', 'Calc_Goals_2', 'Diff_Goals_2'], dtype='object')

示例：

In [26]:

df1 = pd.DataFrame(columns=['Org_Goals_1','Calc_Goals_1','Diff_Goals_1'], data = randn(5,3))
df2 = pd.DataFrame(columns=['Org_Goals_2','Calc_Goals_2','Diff_Goals_2'], data=randn(5,3))
merged = df1.append(df2)
cols = list(df1) + list(df2)
merged.columns = cols
merged
Out[26]:
   Org_Goals_1  Calc_Goals_1  Diff_Goals_1  Org_Goals_2  Calc_Goals_2  \
0     0.028935           NaN     -0.687143          NaN      1.528579   
1     0.943432           NaN     -2.055357          NaN     -0.720132   
2     0.035234           NaN      0.020756          NaN      1.556319   
3     1.447863           NaN      0.847496          NaN     -1.458852   
4     0.132337           NaN     -0.255578          NaN     -0.222660   
0          NaN      0.131085           NaN     0.850022           NaN   
1          NaN     -1.942110           NaN     0.672965           NaN   
2          NaN      0.944052           NaN     1.274509           NaN   
3          NaN     -1.796448           NaN     0.130338           NaN   
4          NaN      0.961545           NaN    -0.741825           NaN   

   Diff_Goals_2  
0           NaN  
1           NaN  
2           NaN  
3           NaN  
4           NaN  
0      0.727619  
1      0.022209  
2     -0.350757  
3      1.116637  
4      1.947526

列的相同alpha排序也会发生在concat中，因此看起来你必须在追加后重新排序。

修改

另一种方法是使用join：

In [32]: df1.join(df2) Out[32]: Org_Goals_1 Calc_Goals_1 Diff_Goals_1 Org_Goals_2 Calc_Goals_2 \ 0 0.163745 1.608398 0.876040 0.651063 0.371263 1 -1.762973 -0.471050 -0.206376 1.323191 0.623045 2 0.166269 1.021835 -0.119982 1.005159 -0.831738 3 -0.400197 0.567782 -1.581803 0.417112 0.188023 4 -1.443269 -0.001080 0.804195 0.480510 -0.660761 Diff_Goals_2 0 -2.723280 1 2.463258 2 0.147251 3 2.328377 4 -0.248114

Answer 3

正如我所看到的，订单已丢失，但在追加时，原始数据应该具有正确的顺序。为了保持这一点，假设Dataframe＆＃39; alldata＆＃39;和数据框作为附加数据＆＃39; newdata＆＃39;，附加并保持列顺序，如＆lt; alldata＆＃39;将是：

alldata.append(newdata)[list(alldata)]

（我在命名的日期字段中遇到了这个问题，其中＆＃39;月＆＃39;将在＆＃39; Minute＆＃39;＆＃39; Second＆＃39;）之间进行排序。

你能阻止df.append（）的自动字母顺序吗？

3 个答案: