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Miscellaneous functions

misc.Rd

This page documents various functions that work for disords, and I will add to these from time to time as I add new functions that make sense for disord objects (or identify functions that break disord discipline). Functions like sin() and abs() work as expected: they take and return disord objects with the same hash as x (which means that idiom like x + sin(x) is accepted). However, there are a few functions that are a little more involved:

  • rev() reverses its argument and returns a disord object with a reversed hash, which ensures that rev(rev(x))==x (and the two are consistent).

  • sort() returns a vector of sorted elements (not a disord)

  • length() returns the length of the data component of the object

  • sapply(X,f) returns a disord object which is the result of applying f() to each element of X.

  • match(x,table) should behave as expected but note that if table is a disord, the result is not defined (because it is not known where the elements of x occur in table). Nevertheless x %in% table is defined and returns a disord object.

  • lapply(x,f) returns disord(lapply(elements(x),f,...),h=hash(x)). Note that double square bracket extraction, as in x[[i]], is disallowed (see extract.Rd).

  • which() returns a disind object when given a Boolean disord

  • unlist() takes a disord list, flattens it and returns a disord vector. It requires the recursive flag of base::unlist() to be TRUE, which it is by default, interpreting this to mean “kill all the structure in any sublists”. If the list comprises only length-one vectors, the returned value retains the same hash as the argument; if not, a new hash is generated.

  • diff() is undefined for disord objects.

  • rbind() and cbind() are undefined for disord objects as they break disord discipline. Function binder() returns a generic, and hopefully informative, error message [the package defines methods for rbind2() and cbind2()]

  • jitter() takes a disord object, jitters the elements, and returns a disord object with the correct hash code.

Arguments

x

Object of class disord

Value

Returns a disord

Author

Robin K. S. Hankin

Note

Some functionality is not yet implemented. Factors, lists, and named vectors do not behave entirely consistently in the package; paste() gives inconsistent results when called with disords.

Also, for() loops are incompatible with disord discipline, as they impose an ordering (for() accesses the .Data slot of its argument, which is a regular R vector). Thus:


> (a <- disord(1:3))
A disord object with hash 555f6bea49e58a2c2541060a21c2d4f9078c3086 and elements
[1] 1 2 3
(in some order)
> for(i in a){print(i)}
[1] 1
[1] 2
[1] 3
>

Above, we see that for() uses the ordering of the .Data slot of S4 object a, even though elements() has not been explicitly called.

See also

extract

Examples

a <- disord(c(a=1,b=2,c=7))
a
#> A disord object with hash 3df571820c0bfd69c157d0b9157beb55eb694d07 and elements
#> [1] 1 2 7
#> (in some order)
names(a)
#> [1] "a" "b" "c"
length(a)
#> [1] 3
sqrt(a)
#> A disord object with hash 3df571820c0bfd69c157d0b9157beb55eb694d07 and elements
#> [1] 1.000000 1.414214 2.645751
#> (in some order)


# powers() and vars() in the mvp package return lists; see the vignette
# for more discussion.

l <- disord(list(3,6:9,1:10))  
sapply(l,length)
#> A disord object with hash 44c762f044d7346be4dbd735de09046c54b79a37 and elements
#> [1]  1  4 10
#> (in some order)

unlist(l)
#> A disord object with hash d836717f8d8d0696972335a7b366805189081e2e and elements
#>  [1]  3  6  7  8  9  1  2  3  4  5  6  7  8  9 10
#> (in some order)

## Quick illustration of rev():

revstring <- function(s){paste(rev(unlist(strsplit(s, NULL))),collapse="")}
x <- rdis()
revstring(hash(x)) == hash(rev(x))
#> [1] TRUE