How to use Indexing Operators in List in R

1. [ ] = always returns a list with a single element.
2. [[ ]] = returns a list element
3. $ = returns elements from list that have names associated with it, not necessarily same class

dat <- list( str='R', vec=c(1,2,3), bool=TRUE )
a = dat["str"]
a
class(a)

b = dat[["str"]]
b
class(b)

c = dat$str
c
class(b)

R Indexing Operators

Both $ and [[ ]] works same. But it is advisable to use [[ ]] in functions and loops. 

dat1[[c("Bal02","ivtable")]]
dat1$Bal02$ivtable