使用R根据其他列创建新变量 [英] Create new variable based on other columns using R

问题描述

我有一个很大的文件，我想在其中基于其他列创建一列。
我的文件如下：

I have a huge file where I want to create a column based on other columns. My file look like this:

person = c(1,2,3,4,5,6,7,8)
father = c(0,0,1,1,4,5,5,7)
mother = c(0,0,2,3,2,2,6,6)
ped = data.frame(person,father,mother)

我想要创建一个指示该人是父亲还是母亲的列（性别列）。在一个小示例中，我使用for循环将其获取，但是当我将其应用于整个文件时，需要花费数小时才能完成。请问如何创建一个Apply函数来解决这个问题。谢谢。

And I want to create a column indicating if the person is a father or mother (gender column). I got it using a for loop in a small example, but when I apply in the whole file it takes hours to finish. How can I create an apply function to solve that, please. Thanks.

for(i in 1:nrow(ped)){
  ped$test[i] = ifelse(ped[i,1] %in% ped[,2], "M", ifelse(ped[i,1] %in% ped[,3], "F", NA)) 
}

推荐答案

尝试一下：

ped <- transform(ped, gender = ifelse(person %in% father,
                                      'M',
                                      ifelse(person %in% mother, 'F', NA)
                                     ))

而不是循环遍历各个值行，这使用矢量化。

Instead of looping over the individual values across the rows, this uses vectorization.

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