pandas :添加交叉表总计 [英] Pandas: add crosstab totals

问题描述

如何向交叉表中添加总计的另一行和另一列?

How can I add to my crosstab an additional row and an additional column for the totals?

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

我以为我会添加新列(通过对行进行求和而获得)

I thought I would add the new column (obtained by summing over the rows) by

ct["Total"] = ct.0 + ct.1

但这不起作用.

推荐答案

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:

This is because 'attribute-like' column access does not work with integer column names. Using the standard indexing:

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

请参阅文档本节末尾的警告: http://pandas.pydata.org/pandas-docs/stable/indexing.html#attribute-access

See the warnings at the end of this section in the docs: http://pandas.pydata.org/pandas-docs/stable/indexing.html#attribute-access

要处理行时，可以使用.loc:

When you want to work with the rows, you can use .loc:

In [126]: ct.loc["Total"] = ct.loc[0] + ct.loc[1]

在这种情况下，ct.loc["Total"]等效于ct.loc["Total", :]

In this case ct.loc["Total"] is equivalent to ct.loc["Total", :]

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