Pandas：添加交叉表总计
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Pandas: add crosstab totals
提问by meto
How can I add to my crosstab an additional row and an additional column for the totals?
如何在交叉表中为总计添加额外的行和额外的列？
df = pd.DataFrame({"A": np.random.randint(0,2,100), "B" : np.random.randint(0,2,100)})
ct = pd.crosstab(new.A, new.B)
ct
I thought I would add the new column (obtained by summing over the rows) by
我以为我会添加新列（通过对行求和获得）
ct["Total"] = ct.0 + ct.1
but this does not work.
但这不起作用。
采纳答案by joris
This is because 'attribute-like' column access does not work with integer column names. Using the standard indexing:
这是因为“类似属性”的列访问不适用于整数列名。使用标准索引：
In [122]: ct["Total"] = ct[0] + ct[1]
In [123]: ct
Out[123]:
B 0 1 Total
A
0 26 24 50
1 30 20 50
See the warnings at the end of this section in the docs: http://pandas.pydata.org/pandas-docs/stable/indexing.html#attribute-access
请参阅文档中本节末尾的警告：http: //pandas.pydata.org/pandas-docs/stable/indexing.html#attribute-access
When you want to work with the rows, you can use .loc:
当您想处理行时，可以使用.loc：
In [126]: ct.loc["Total"] = ct.loc[0] + ct.loc[1]
In this case ct.loc["Total"]is equivalent to ct.loc["Total", :]
在这种情况下ct.loc["Total"]相当于ct.loc["Total", :]
回答by Ida
In fact pandas.crosstabalready provides an option margins, which does exactly what you want.
事实上pandas.crosstab已经提供了一个选项margins，它完全符合你的要求。
> df = pd.DataFrame({"A": np.random.randint(0,2,100), "B" : np.random.randint(0,2,100)})
> pd.crosstab(df.A, df.B, margins=True)
B 0 1 All
A
0 26 21 47
1 25 28 53
All 51 49 100
Basically, by setting margins=True, the resulting frequency table will add an "All" column and an "All" row that compute the subtotals.
基本上，通过设置margins=True，生成的频率表将添加一个“全部”列和一个“全部”行来计算小计。
回答by Shiny
You should use the margins=True for this along with crosstab. That should do the job!
为此，您应该将 margins=True 与交叉表一起使用。那应该做的工作！
