您可以将 apply 应用于原始数据的子集.

You can apply apply to a subset of the original data.

 dat <- data.frame(x=c(1,2), y=c(3,4), z=c(5,6))
 apply(dat[,c('x','z')], 1, function(x) sum(x) )

或者如果您的函数只是求和，请使用矢量化版本:

or if your function is just sum use the vectorized version:

rowSums(dat[,c('x','z')])
[1] 6 8

如果你想使用 testFunc

 testFunc <- function(a, b) a + b
 apply(dat[,c('x','z')], 1, function(x) testFunc(x[1],x[2]))

EDIT 要按名称而不是索引访问列，您可以执行以下操作:

EDIT To access columns by name and not index you can do something like this:

 testFunc <- function(a, b) a + b
 apply(dat[,c('x','z')], 1, function(y) testFunc(y['z'],y['x']))