Extract or Replace elements of permutation vectors

Methods for "[" and "[<-", i.e., extraction or subsetting of permutation vectors.

Value

Extraction and methods return an onion or onionmat. Replacement methods return an object of the same class as the right hand side.

Details

Extraction and replacement for word form uses array-based indexing. Cycle form uses list-based indexing and is thus less flexible.

Author

Robin K. S. Hankin

Note

Notes here

Examples

(a <- rperm(9))
#> [1] (15376)(24) (1457263)   (1746)(253) (13625)     (1765)(243) (1764253)  
#> [7] (15673)     (165)(47)   (1253)(67) 
#> [coerced from word form]
a[1:3]
#> [1] (15376)(24) (1457263)   (1746)(253)
#> [coerced from word form]
a[5:7] <- id  # word form: multiple replacements allowed.
a
#> [1] (15376)(24) (1457263)   (1746)(253) (13625)     ()          ()         
#> [7] ()          (165)(47)   (1253)(67) 
#> [coerced from word form]

x <- as.cycle(rperm(9))
x
#> [1] (137)(46)   (165324)    (132)(56)   (17563)(24) (146)(37)   (13)(24567)
#> [7] (274)(356)  (2463)(57)  (1367254)  
x[5] <- x[4] * x[6]  # cycle form: replacement takes only a single index.
x
#> [1] (137)(46)   (165324)    (132)(56)   (17563)(24) (12576)     (13)(24567)
#> [7] (274)(356)  (2463)(57)  (1367254)