as.data.frame.rdeque: Convert an rdeque to a data.frame

In rstackdeque: Persistent Fast Amortized Stack and Queue Data Structures

Description

Converts the elements of an rdeque into rows of a data.frame, if this is reasonable.

Usage

## S3 method for class 'rdeque'
as.data.frame(x, row.names = NULL, optional = FALSE, ...)

Arguments

x	rdeque to convert.
row.names	passed on to as.data.frame before final conversion.
optional	passed onto as.data.frame before final conversion.
...	passed onto as.data.frame before final conversion.

Details

This function runs in O(N) time in the size of the rdeque, and will only work if all elements of the deque have the same length() (e.g., same number of columns), and if any of the elements have names, then those names do not conflict (e.g., same column names where used). This is accomplished by a call to do.call("rbind", as.list.rdeque(x)), where as.list.rdeque converts the rdeque to a list where the front element becomes the first element of the list.

Value

a data.frame with the first row the previous front of the deque and last row the previous back.

See Also

as.list.rdeque for conversion to a list and the generic as.data.frame.

Examples

d <- rdeque()
d <- insert_front(d, data.frame(names = c("Bob", "Joe"), ages = c(25, 18)))
d <- insert_front(d, data.frame(names = c("Mary", "Kate", "Ashley"), ages = c(27, 26, 21)))
print(d)

dd <- as.data.frame(d)
print(dd)

## Elements may be similarly-named lists as well, representing individual rows:
d <- rdeque()
d <- insert_front(d, list(name = "Bob", age = 25))
d <- insert_front(d, list(name = "Mary", age = 24))
print(d)

dd <- as.data.frame(d)
print(dd)

## Building a deque in a loop, converting to a dataframe after the fact:
d <- rdeque()
for(i in 1:1000) {
 if(runif(1,0,1) < 0.5) {
   d <- insert_front(d, data.frame(i = i, type = "sqrt", val = sqrt(i)))
 } else {
   d <- insert_back(d, data.frame(i = i, type = "log", val = log(i)))
 }
 if(i %% 100 == 0) {
   print(i/1000)
 }
}
print(head(as.data.frame(d)))

rstackdeque documentation built on May 2, 2019, 4:15 a.m.