更改R数据框中的列值

Question

我在R中有一个这样格式的数据框:

如何调用GROUP等于B的所有HEIGHT值并更改它们？即从cm到mm.

Answer 1

data = data.frame(group = rep(c("A", "B", "C"), each = 4), height = c(259, 243, 253, 235, 23.5, 23.6, 23.5, 24.1, 235, 234, 235, 220))
data #shows your data
data$height[data$group == "B"]  <- data$height[data$group == "B"] * 10 #from cm to mm

HTH