datastructures (version 0.2.9)

peek: Have a look at the first element from an object without removing it

Description

Peeks into an object, i.e. takes the first element and returns it without removing it from the object. The data structure that has a peek method usually uses some sort of priority of its elements.

Usage

peek(obj)
# S4 method for deque
peek(obj)
# S4 method for heap
peek(obj)
# S4 method for map
peek(obj)

Arguments

obj

the object to peek

Value

returns the first element from obj as list

Examples

# NOT RUN {
 # peeks into a queue
 q <- queue()
 q <- insert(q, list(environment(), data.frame(a=1)))
 peek(q)

 # peeks into a fibonacci heap
 b_heap <- binomial_heap()
 b_heap <- insert(b_heap, letters[seq(3)], list(1, diag(3), rnorm(2)))
 peek(b_heap)

 # peeks into a \code{hashmap}
 h_map <- hashmap()
 h_map[letters] <- rnorm(length(letters))
 peek(h_map)

 # peeks into a \code{bimap}
 b_map <- bimap("integer", "integer")
 b_map[seq(10)] <- seq(10, 1)
 peek(b_map)

# }