CODEWITHSUNDEEP
rlistelement
David K.
David K.

Reputation: 84

R remove element from list

How do I remove an element from a list in R? Imagine this workflow:

# create list
my_list <- lapply(1:10, function(x) x)
# find which ones to exclude
my_list_boolean <- sapply(my_list, function(x) ifelse(x%%2>0,F,T))
# does not work like this!
my_list[[my_list_boolean]]

Is there a solution not having to use a for loop and create a big logic around my statement?

Upvotes: 0

Views: 1429

Answers (2)

cderv
cderv

Reputation: 6542

Just use [] and not [[]] 

my_list <- lapply(1:10, function(x) x)
# find which ones to exclude
my_list_boolean <- sapply(my_list, function(x) ifelse(x%%2>0,F,T))
# does not work like this!
my_list[my_list_boolean]
#> [[1]]
#> [1] 2
#> 
#> [[2]]
#> [1] 4
#> 
#> [[3]]
#> [1] 6
#> 
#> [[4]]
#> [1] 8
#> 
#> [[5]]
#> [1] 10

Created on 2018-11-03 by the reprex package (v0.2.1)

You can thus select element of the list with logical vector and not the content (which is [[]]

Upvotes: 1

Maurits Evers
Maurits Evers

Reputation: 50668

Do you mean this?

my_list[my_list_boolean]
#[[1]]
#[1] 2
#
#[[2]]
#[1] 4
#
#[[3]]
#[1] 6
#
#[[4]]
#[1] 8
#
#[[5]]
#[1] 10

Upvotes: 1

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