为什么我的Pandas DataFrame不使用`sort_values`显示新订单? [英] Why does my Pandas DataFrame not display new order using `sort_values`?

问题描述

Pandas的新手，所以也许我错过了一个大主意? 我有一个形状像(500,4):

New to Pandas, so maybe I'm missing a big idea? I have a Pandas DataFrame of register transactions with shape like (500,4):

Time              datetime64[ns]
Net Total                float64
Tax                      float64
Total Due                float64

我正在使用 Python3 Jupyter笔记本处理代码.我无法对任何列进行排序.通过不同的代码示例进行排序，检查df时看不到输出重新排序.因此，我已将问题减少为尝试仅订购一列:

I'm working through my code in a Python3 Jupyter notebook. I can't get past sorting any column. Working through the different code examples for sort, I'm not seeing the output reorder when I inspect the df. So, I've reduced the problem to trying to order just one column:

df.sort_values(by='Time')
# OR
df.sort_values(['Total Due'])
# OR
df.sort_values(['Time'], ascending=True)

无论我使用哪个列标题或哪个布尔参数，显示的结果都不会改变顺序.

No matter which column title, or which boolean argument I use, the displayed results never change order.

考虑到这可能是Jupyter的事情，我已经使用print(df)，df.head()和HTML(df.to_html())预览了结果(最后一个示例是针对Jupyter笔记本的).我还将整个笔记本从导入CSV重新运行到此代码.而且，我也是Python3的新手(从2.7开始)，因此有时会遇到这种情况，但是在这种情况下我看不出这有什么用.

Thinking it could be a Jupyter thing, I've previewed the results using print(df), df.head(), and HTML(df.to_html()) (the last example is for Jupyter notebooks). I've also rerun the whole notebook from import CSV to this code. And, I'm also new to Python3 (from 2.7), so I get stuck with that sometimes, but I don't see how that's relevant in this case.

另一篇帖子也有类似的问题， Python pandas数据框sort_values不起作用.在这种情况下，排序是在列类型string上进行的.但是正如您所看到的，这里的所有列都是明确可排序的.

Another post has a similar problem, Python pandas dataframe sort_values does not work. In that instance, the ordering was on a column type string. But as you can see all of the columns here are unambiguously sortable.

为什么我的Pandas DataFrame不使用sort_values显示新订单?

Why does my Pandas DataFrame not display new order using sort_values?

推荐答案

df.sort_values(['Total Due'])返回已排序的DF，但不会就地更新DF.

df.sort_values(['Total Due']) returns a sorted DF, but it doesn't update DF in place.

因此要明确地这样做:

df = df.sort_values(['Total Due'])

或

df.sort_values(['Total Due'], inplace=True)

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