从data.frame创建二进制矩阵 [英] create binary matrix from data.frame

问题描述

如何从具有两列的data.frame中创建二进制矩阵，其中第一列表示例如物种和其他地区?data.frame的格式如下所示

How can I create a binary matrix from a data.frame with two columns where the first column represents e.g. species and the other their region? The data.frame is in tall format as seen below

species region
species1 1
species1 2
species1 3
species2 2
species2 4
species2 5
species2 6
species3 1
species3 2
species4 5
species5 3
species5 4

并且矩阵会将所有唯一的物种作为行，并将所有唯一的区域作为列.对于存在的物种，矩阵将填充为 1s ，对于不存在的物种将填充为 0s ，如下所示

And the matrix would have all unique species as rows and all unique regions as columns. The matrix would be filled with 1s for species present and 0s for species absent, as below

         1  2  3  4  5  6
species1 1  1  1  0  0  0
species2 0  1  0  1  1  1
species3 1  1  0  0  0  0
species4 0  0  0  0  1  0
species5 0  0  1  1  0  0

非常感谢任何指针，谢谢！

Any pointers would be very much appreciated, thanks!

推荐答案

您正在寻找函数 table ，其文档为

You are looking for the function table whose documentation is here

如果您的data.frame是 df ，则只需要做

If your data.frame is df, you just have to do

table(df)

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