spray (version 1.0-8)

Extract.spray: Extract or Replace Parts of a spray

Description

Extract or replace subsets of sprays.

Usage

# S3 method for spray
[(S, …, drop=FALSE)
# S3 method for spray
[(S, index, …) <- value

Arguments

S

A spray object

index

elements to extract or replace

value

replacement value

...

Further arguments

drop

Boolean, with default FALSE meaning to return a spray object and TRUE meaning to drop the spray structure and return a numeric vector

Details

These methods should work as expected, although the off-by-one issue might be a gotcha.

If drop is TRUE, a numeric vector is returned but the elements may be in any order.

If a <- spray(diag(3)), for example, then idiom such as a[c(1,2,3)] cannot work, because one would like a[1,2,3] and a[1:3,2,3] to work.

Examples

# NOT RUN {
a <- spray(diag(5))
a[rbind(rep(1,5))] <- 5

a[3,4,5,3,1]  # the NULL polynomial

a[0,1,0,0,0]
a[0,1,0,0,0,drop=TRUE]

a[2,3:5,4,3,3] <- 9


options(polyform = TRUE)   # print as a multivariate polynomial
a

options(polyform = FALSE)  # print is sparse array form
a


S1 <- spray(diag(5),1:5)
S2 <- spray(1-diag(5),1:5)
S1[] <- 3
S1[] <- S2




# }