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rlistiterationkey-valuesapply

Iterate over list to get value by its name

This works. But are there more efficient/simpler ways to get output?

test_list <- list(list("name"="A","property"=1),
              list("name"="B","property"=2),
              list("name"="C","property"=3))

myFunction <- function(arg1=NULL, arg2=NULL){
  arg1[[arg2]]
}

# works
output <- sapply(test_list, myFunction, "property")

# returns NULL 
# output <- sapply(test_list, `$`, "property")
Solution

  • We can specify the anonymous function call to do the extraction

    sapply(test_list, function(x) x$property)
#[1] 1 2 3