根据其他列中的二进制值创建新的条件列？ （右）

Question

My data looks like this:

A   B   C
1   0   0
0   1   0
0   1   0
0   0   1

This is what I'm going for:

A   B   C   New_Column
1   0   0   A
0   1   0   B
0   1   0   B
0   0   1   C

So I'm creating a new column that tells me which of the three variables (A, B, or C) is present. Only one of the three columns will contain a 1 per row. What is the best way to go about this?

Answer 1

我们可以使用max.col

df1$New_Column <- names(df1)[max.col(df1, "first")]