有没有像pmax索引的东西？ [英] Is there something like a pmax index?

问题描述

我有一个包含以下数据的数据框：

I have a data frame with the following data:

date=strptime(c(20110101,20110102,20110103,20110104,20110105,20110106),'%Y%m%d')
rate1=c(1,2,3,4,5,6)
rate2=c(2,1,3,6,8,4)
rate3=c(4,1,3,6,8,3)
rate4=c(7,8,9,2,1,8)
z=data.frame(date,rate1,rate2,rate3,rate4)
z$max=pmax(rate1,rate2,rate3,rate4)

pmax函数允许我获取该记录的最大值，但我想知道如何获取该记录的最大值的索引。

The pmax function allows me to get the maximum value for that record, but I was wondering how I can get the index of the maximum value for that record.

其中z $ max将等于 7,8,9,6,8,8 ，我想获得 5 ，5,5,3,3,5

Where z$max would equal 7,8,9,6,8,8, I would like to get 5,5,5,3,3,5

这可能吗？我知道这似乎是一些简单的东西，但是我无法找到答案。

Is this possible? I know this seems like something simple but I cannot find the answer anywhere.

推荐答案

Very simple in base R:

z$wmax <- apply(z[, -c(1,6)],1, which.max)

实际上，这比您排除第一列少于1次，但您可以轻松补救添加一个。

Actually that gives you 1 less than what you were asking for since I excluded the first column but that can easily be remedied by adding one.

z$max_col_n <- apply(z[, -c(1,6)],1, which.max) +1

这篇关于有没有像pmax索引的东西？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！