以所有可能的组合耦合数据 [英] Couple the data in all possible combinations

问题描述

我在这样的两列中都有数据

I have data in column in two columns like this

Id  Value
1   a
2   f
1   c
1   h
2   a

并且我想基于相同的ID(例如，

and I'd like couple the data of the 'Value' column in all possible combinations based on the same Id such as

(a,c)
(a,h)
(c,h)
(f,a)

是否有R或Python或VBA代码可以完成此任务?

Is there any R or Python or VBA code to get this task?

推荐答案

要使用底数R返回具有这些组合的字符矩阵，请尝试

To return a character matrix with these combinations using base R, try

do.call(rbind, t(sapply(split(df, df$Id), function(i) t(combn(i$Value, 2)))))
     [,1] [,2]
[1,] "a"  "c" 
[2,] "a"  "h" 
[3,] "c"  "h" 
[4,] "f"  "a"

每行都是所需的组合.

为了稍微分解一下，split将ID将data.frame拆分为两个data.frame的列表.然后，将sapply馈入此列表和combn函数，以在这些data.frames中查找成对组合.使用t将每个data.frame(它是矩阵)的结果转置为适合您所需的结构.最后，此矩阵列表被馈送到do.call，后者使用rbind返回最终矩阵.

To break this down a bit, split splits the data.frame by Id into a list of two data.frames. Then sapply is fed this list and the combn function to find the pairwise combinations within these data.frames. The result from each data.frame (which is a matrix) is transposed to fit your desired structure using t. Finally, this list of matrices is fed to do.call which uses rbind to return the final matrix.

注意:假设值列是字符(不是讨厌因素变量类型).在read.函数族(例如read.csv和read.table)中，可以通过将as.is = TRUE参数添加到读取函数(或更长的stringsAsFactors = FALSE)中来轻松实现此目的.如果变量已经是一个因素，则可以将i$Value语句包装在as.character:as.character(i$Value)的结尾处，它将按需运行.

Note: There is an assumption that the value column is character (not the pesky factor variable type). This is easily accomplished in the read. family of functions, like read.csv and read.table by adding the as.is=TRUE argument to your read function (or the longer stringsAsFactors=FALSE). If the variable is already a factor, you can wrap the i$Value statement near the end in as.character: as.character(i$Value) and it will run as desired.

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