将R因子转换为二进制矩阵值 [英] Converting R Factors into Binary Matrix Values

问题描述

我想将数据框转换为一个矩阵，该矩阵将一个因子列扩展为多个因子列，并根据因子分配一个1/0.例如

I would like to convert my dataframe into a matrix that expands a single factor column into multiple ones and assigns a 1/0 depending on the factor. For example

C1 C2 C3
A  3  5
B  3  4
A  1  1

应该变成类似

C1_A C1_B C2 C3
1      0  3  5
0      1  3  4
1      0  1  1

如何在R中做到这一点?我尝试了data.matrix，as.matrix，但没有返回我想要的内容.他们为单个因子列分配一个整数"值，没有扩展.

How can I do this in R? I tried data.matrix, as.matrix which did not return what I wanted. They assign an "integer" value to a single factor column, there is no expansion.

推荐答案

假设dat是您的数据框:

cbind(dat, model.matrix( ~ 0 + C1, dat))

  C1 C2 C3 C1A C1B
1  A  3  5   1   0
2  B  3  4   0   1
3  A  1  1   1   0

此解决方案适用于任意数量的因子水平，而无需手动指定列名.

This solution works with any number of factor levels and without manually specifying column names.

如果要排除列C1，则可以使用以下命令:

If you want to exclude the column C1, you could use this command:

cbind(dat[-1], model.matrix( ~ 0 + C1, dat))

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