Naming list elements in R based on applied functions

Question

I have a set of functions funs <- c(mean, median, min, max, quantile) which I want to apply to a numeric vector values. This can easily done with sapply() but with its result none of the elements has a name. I want each list element named based on the applied function. I tried:

funs <- c(mean, median, min, max, quantile)
some_vals <- c(rnorm(14))

stats <- sapply(funs, function(fun) {
    result <- fun(some_vals)
    names(result) <- deparse(substitute(fun))
    return(result)
    }
)

But with that every list element is named X[[i]]. How can I name the list elements according to the applied function(s)?

Answer 1

The difficulty is that once you store the functions objects inside a list, they no longer have a name unless you specify a name for that object in the list.

I would use strings for the function names then match.fun inside sapply. This is easy to do and you get the names for free.

funs <- c("mean", "median", "min", "max", "quantile")
some_vals <- c(rnorm(14))

sapply(funs, function(fun) match.fun(fun)(some_vals))
#> $mean
#> [1] -0.06134755
#> 
#> $median
#> [1] -0.3473996
#> 
#> $min
#> [1] -2.140686
#> 
#> $max
#> [1] 1.940046
#> 
#> $quantile
#>         0%        25%        50%        75%       100% 
#> -2.1406864 -0.7488198 -0.3473996  0.7707063  1.9400459

The alternative is to name your list:

funs <- c(mean = mean, median = median, min = min, max = max, 
          quantile = quantile)

sapply(funs, function(fun) fun(some_vals))
#> $mean
#> [1] -0.06134755
#> 
#> $median
#> [1] -0.3473996
#> 
#> $min
#> [1] -2.140686
#> 
#> $max
#> [1] 1.940046
#> 
#> $quantile
#>         0%        25%        50%        75%       100% 
#> -2.1406864 -0.7488198 -0.3473996  0.7707063  1.9400459

^{Created on 2023-08-21 with reprex v2.0.2}