What is the right way to multiply data frame by vector?

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This works too:

data.frame(mapply(`*`,df,v))

In that solution, you are taking advantage of the fact that data.frame is a type of list, so you can iterate over both the elements of df and v at the same time with mapply.

Unfortunately, you are limited in what you can output from mapply: as simple list, or a matrix. If your data are huge, this would likely be more efficient:

data.frame(mapply(`*`,df,v,SIMPLIFY=FALSE))

Because it would convert it to a list, which is more efficient to convert to a data.frame.

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