# Weighted mean with summarise_at dplyr

I strictly need to use the summarise_at to compute a weighted mean, with weights based on the values of another column

    df %>% summarise_at(.vars = vars(FACTOR,tv:smart tv/console),
.funs = weighted.mean, w=INVESTMENT, na.rm=TRUE)


It always shows the error: 'INVESTMENT' is not found.

I then tried with:

df %>%summarise_at(.vars = vars(FACTOR,tv:smart tv/console),
.funs = weighted.mean, w=vars(INVESTMENT), na.rm=TRUE)


But in this case : Evaluation error: 'x' and 'w' must have the same length.

Why is this? Am I doing anything wrong? Do you have hints to solve this issue? Thanks

You can specify the weights directly within the weighted.mean() function, within the call to funs() like so:

data.frame(x=rnorm(100), y=rnorm(100), weight=runif(100)) %>%
summarise_at(vars(x,y), funs(weighted.mean(., w=weight)))

• summarise_at has now been superseded by across. Your example code may now look something like this: data.frame(x=rnorm(100), y=rnorm(100), weight=runif(100)) %>% summarise(across(x:y, ~weighted.mean(., w = weight))) – JPD Sep 23 at 8:15