在R中的if语句中使用for循环

使用简单的乘法

set.seed(1223)
g.rates[x[, 5], ] * x[, -5]  # Note in your question you missed to include Typ2.rates 

或者使用data.table

library(data.table)
setDT(x)[, .SD*g.rates[x$Type,] , .SDcols = paste0("V", 1:4)]
#        V1        V2        V3         V4
#1 141.8580 1149.9857  303.4235 1014.77952
#2 770.1482  407.0248 1219.3383  156.62141
#3 554.1117  983.2340  239.1585   50.52443
#4 584.8300 1207.7605 2252.7681   43.13052