具有行方式最大值的列索引

Question

我有以下数据:

  Newspaper    Month Year          Date      Topic1      Topic2     Topic3      Topic4      Topic5
1  Scotsman December 2005 December 2005 0.013749700 0.000127470 0.38575261 0.000127470 0.070778523
2  Scotsman December 2005 December 2005 0.000165017 0.000165017 0.05219433 0.004611941 0.000165017
3  Scotsman December 2005 December 2005 0.000356507 0.024344932 0.01135670 0.000356507 0.000356507
4  Scotsman December 2005 December 2005 0.000185186 0.000185186 0.10796924 0.044639345 0.106613401
5  Scotsman December 2005 December 2005 0.065869506 0.009775978 0.09610254 0.017584819 0.000103681
6  Scotsman December 2005 December 2005 0.000153257 0.000153257 0.11443001 0.000153257 0.046316677

我想创建一个单独的变量,对应于TopicN更高的百分比.

在第一篇文章(行)的情况下,它将是3.任何想法？

Answer 1

您可以max.col()在主题列上使用.如果df是数据,请尝试

max.col(df[grepl("^Topic", names(df))])
# [1] 3 3 2 3 3 3

所以要添加一个新列MaxPct,我们可以做到

df$MaxPct <- max.col(df[grepl("^Topic", names(df))])