Is it possible to index an R list using a character variable and the '$' operator? -


can explain why null in following ?

> =  list( 'key'='val') > a$'key' [1] "val" > a$key [1] "val" > key_var = 'key' > a$key_var null

i know can 

> a[[key_val]] [1] "val"

but think double brackets can messy (especially when working nested lists, etc).


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