hyper2 (version 3.2)

Extract: Extract or replace parts of a hyper2 object

Description

Extract or replace parts of a hyper2 object

Usage

# S3 method for hyper2
[(x, ...)
# S3 method for hyper2
[(x, index, ...) <- value
assign_lowlevel(x,index,value)
overwrite_lowlevel(x,value)

Value

The extractor method returns a hyper2 object, restricted to the elements specified

Arguments

x

An object of class hyper2

...

Further arguments, currently ignored

index

A list with integer vector elements corresponding to the brackets whose power is to be replaced

value

Numeric vector of powers

Author

Robin K. S. Hankin

Details

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

For the extract method, H[L], a hyper2 object is returned. The replace method, H[L] <- value, the index specifies the brackets whose powers are to be overwritten; standard disordR protocol is used.

If the index argument is missing, viz H1[] <- H2, this is a special case. Argument H1 must be a hyper2 object, and the idiom effectively executes H1[brackets(H2)] <- powers(H2), but more efficiently (note that this operation is well-defined even though the order of the brackets is arbitrary). This special case is included in the package because it has a very natural C++ expression [function overwrite() in the src/ directory] that was too neat to omit.

Altering (incrementing or decrementing) the power of a single bracket is possible using idiom like H[x] <- H[x] + 1; this is documented at Ops.hyper2, specifically hyper2_sum_numeric() and a discussion is given at increment.Rd.

Functions assign_lowlevel() and overwrite_lowlevel() are low-level helper functions and not really intended for the end-user.

See Also

hyper2,Ops.hyper2

Examples

data(chess)

chess["Topalov"]
chess[c("Topalov","Anand")]
chess[c("Anand","Topalov")]

# Topalov plays Anand and wins:

chess["Topalov"] <- chess["Topalov"]+1 
chess[c("Topalov","Anand")] <- chess[c("Topalov","Anand")]-1


# Topalov plays *Kasparov* and wins:
chess["Topalov"] <- chess["Topalov"] + 1
chess[c("Topalov","Kasparov")] <- chess[c("Topalov","Kasparov")] -1

# magrittr idiom:
# chess["Topalov"] %<>% inc
# chess[c("Topalov","Kasparov")] %<>% dec  

# overwriting idiom:
H <- hyper2(list("Topalov","X"),6)
chess[] <- H

H <- icons