In R how to operate in a list with names-CodePudding

This is my list

list_names <- vector(mode = 'list')

list_names[['NAME A']] <- rnorm(n = 10,sd = 2)
list_names[['NAME B']] <- rnorm(n = 10,sd = 2)
list_names[['NAME C']] <- rnorm(n = 10,sd = 2)
list_names[['NAME D']] <- rnorm(n = 10,sd = 2)
list_names[['NAME E']] <- rnorm(n = 10,sd = 2)
list_names[['NAME F']] <- rnorm(n = 10,sd = 2)

Is it possible to select others elements of list doing something like this:

list_names[[-"NAME A"]]

The output should be a list with all elements except the "NAME A" element?

CodePudding user response：

Probably this is what you are after

list_names[-match('NAME A',names(list_names))]

!! WARNING: if the requested name is not a valid name of list_names, then the solution will return NULL (thanks for @akrun's comment)

CodePudding user response：

We need [ and not [[ for selecting more than one element from a list. Also, - wouldn't work, instead use setdiff

list_names[setdiff(names(list_names), "NAME A")]

-output

$`NAME B`
 [1] -3.237378  4.082310  1.330150  1.784154  1.360302  5.530083 -4.593817 -2.021845 -2.278811  5.359281

$`NAME C`
 [1]  0.7641719 -0.9874008  0.9278225 -0.9709333 -0.1113175 -0.2290865 -0.2682319  2.8789682  0.6797194 -1.8765561

$`NAME D`
 [1]  3.8257606 -3.0235199 -3.4250881 -0.1333553  0.1202357  0.3694179 -2.0254176 -1.9489545  1.1015625  2.5311685

$`NAME E`
 [1]  2.4825388 -0.9485210 -2.7486256 -1.1970403 -1.3655852 -0.4481327 -2.0552594  0.3480588  1.9688285  1.1266358

$`NAME F`
 [1]  2.7535404  1.9831037 -2.3185156  0.5392882  1.0800234 -3.3278948 -1.7413377 -1.9040359  1.2478318  1.2664443

Or another option is a logical vector

list_names[names(list_names) != "NAME A"]

CodePudding user response：

You can negate %in% and provide a vector of names to exclude which will work with any number of names. This also tolerates names that are not members of names(l) without returning an error.

l <- list(a = 1:3,
          b = 1:3,
          c = 1:3)

exclude_names <- "a"

l[!names(l) %in% exclude_names]
#> $b
#> [1] 1 2 3
#> 
#> $c
#> [1] 1 2 3

^{Created on 2022-11-21 with reprex v2.0.2}

CodePudding user response：

Another option is using purrr After identifying NAME A we could zap it:

purrr::list_modify(list_names,`NAME A`=purrr::zap())

$`NAME B`
 [1] -0.8390912  1.3642602  0.5660608 -0.9540717 -0.3867816 -0.2885152  2.2319706 -1.3307411 -1.6760324  1.2665064

$`NAME C`
 [1] -2.2107425  2.2710206  1.9398283  0.8652335  1.7688116  0.4958797 -0.6015274  1.3835770  3.7064383  0.8566645

$`NAME D`
 [1]  0.59945041 -2.35641913  0.58695111  0.42641701  1.16167489  0.05766859  1.37930744  0.18369875  0.62319538
[10] -0.36985800

$`NAME E`
 [1]  4.197209 -3.543006  2.558110  3.378172 -2.749093  1.549671 -1.237776  4.361019  1.611182 -1.038159

$`NAME F`
 [1] -0.3487643  1.0043091 -0.5399112  1.0901489  0.5731137 -1.2881900  1.0738251  1.8890504  1.0534804  0.4025011