strrep: Duplicate Strings#

Description#

Concatenate a number of copies of each string.

Usage#

strrep(x, times)

e1 %x*% e2

Arguments#


`e1`, `x`	character vector (or an object coercible to) whose elements are to be duplicated
`e2`, `times`	numeric vector giving the number of times to repeat the corresponding strings

Details#

Both arguments are recycled if necessary.

The `%x*%` operator mimics a vectorised version of Python’s `*` for strings (str.__mul__).

Value#

A character vector (in UTF-8).

`%x*%` and strrep preserve object attributes in a similar way as other Arithmetic operators.

Differences from Base R#

Replacement for base strrep implemented with stri_dup.

partial recycling with no warning “longer object length is not a multiple of shorter object length” [fixed here]
base strrep seems to preserve only the names attribute, and only if the input is of type character (whilst paste preserves nothing) [fixed]
overloading `*.character` has no effect in R, because S3 method dispatch is done internally with hard-coded support for character arguments. We could have replaced the generic `*` with the one that calls UseMethod, but it feels like a too intrusive solution [fixed by introducing `%x+%` operator]

Author(s)#

Marek Gagolewski

Examples#

x <- structure(c(A="a", B=NA, C="c"), attrib1="value1")
x %x*% 3
##     A     B     C 
## "aaa"    NA "ccc" 
## attr(,"attrib1")
## [1] "value1"
x %x*% 1:3
##     A     B     C 
##   "a"    NA "ccc" 
## attr(,"attrib1")
## [1] "value1"
"a" %x*% 1:3
## [1] "a"   "aa"  "aaa"
stringx::strrep(x, 3)
##     A     B     C 
## "aaa"    NA "ccc" 
## attr(,"attrib1")
## [1] "value1"
base::strrep(x, 3)
##     A     B     C 
## "aaa"    NA "ccc"
y <- matrix(1:6, nrow=2, dimnames=list(c("A", "B"), NULL))
y %x*% 1:2
## [1] "1"  "22" "3"  "44" "5"  "66"
stringx::strrep(y, 1:2)
## [1] "1"  "22" "3"  "44" "5"  "66"
base::strrep(y, 1:2)
## [1] "1"  "22" "3"  "44" "5"  "66"