CODEWITHSUNDEEP
rlist
Chris
Chris

Reputation: 55

How to remove an element from a list by matching parts of its name?

I have a list like: 

    foo<- list(c("foob.10.27808", "foob.11.31809","foob.12.35810","foob.13.39811", 
         "foob.14.43812", "foob.15.47813", "foob.16.51814", "foob.17.<NA>", 
         "foob.5.7803", "foob.6.11804", "foob.7.15805", "foob.8.19806", 
         "foob.9.23807")

Now I want to remove the object with the name "foob.17.<NA>. This should be no problem if I want to do it manually like foo$foob.17.<NA><-NULL or if I would exacly know what its name is, but first I don't want to do it manually (of course not ;)) and second, I don't know its name in every case. Those lists are created inside a function so the only part of its name I do know is ".<NA>".

Is there a way to find the name only by matching it with ".<NA>" an remove it afterwards? Like it's done with environment elements with rm(list=ls(pattern="foo"))?

Thank you in advance.

Best regards, Chris

Upvotes: 0

Views: 51

Answers (1)

G. Grothendieck
G. Grothendieck

Reputation: 269481

Actually foo$"foob.17.<NA>" <- NULL will not work because the list has no component with the name "ffoob.17.<NA>" . The list has only one component and that component contains a character vector.

grep can be used:

list(grep(".<NA>", foo[[1]], value = TRUE, invert = TRUE, fixed = TRUE))

## [[1]]
##  [1] "foob.10.27808" "foob.11.31809" "foob.12.35810" "foob.13.39811"
##  [5] "foob.14.43812" "foob.15.47813" "foob.16.51814" "foob.5.7803"  
##  [9] "foob.6.11804"  "foob.7.15805"  "foob.8.19806"  "foob.9.23807"

If you meant to write foo2 where foo2 is shown below then we can use Filter:

foo2 <- as.list(foo[[1]])
Filter(function(x) !grepl(".<NA", x, fixed = TRUE), foo2)

or if you meant you have a list whose names are the character vector foo[[1]] as shown below then:

foo3 <- setNames(as.list(seq_along(foo[[1]])), foo[[1]])
foo3[ grep(".<NA>", names(foo3), invert = TRUE, fixed = TRUE) ]

Note: foo in the question had unbalanced parentheses so here it is in reproducible form with that fixed:

foo<- list(c("foob.10.27808", "foob.11.31809","foob.12.35810","foob.13.39811", 
         "foob.14.43812", "foob.15.47813", "foob.16.51814", "foob.17.<NA>", 
         "foob.5.7803", "foob.6.11804", "foob.7.15805", "foob.8.19806", 
         "foob.9.23807"))

Upvotes: 3

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