AnriRForLoop

library(tidyverse)
# create named list
l <- list(x = data.frame(a = rnorm(10), b = rnorm(10)),
                     y = data.frame(a = rnorm(10), b = rnorm(10)),
                                z = data.frame(a = rnorm(10), b = rnorm(10)))
          

for (i in names(l)){
  if (i %in% c("x", "y")){ # if the name of the list item is in a specified sublist
    l[[i]] <- l[[i]] %>% mutate(c = a + 1) # then do the mutate
    }
  }