Some utility functions to operate on strings
Some low-level string utilities to operate on ordinary character vectors. For more advanced string manipulations, see the Biostrings package.
unstrsplit(x, sep="") ## more to come...
x |
A list-like object where each list element is a character vector, or a character vector (identity). |
sep |
A single string containing the separator. |
unstrsplit(x, sep) is equivalent to (but much faster than)
sapply(x, paste0, collapse=sep). It performs the reverse
transformation of strsplit( , fixed=TRUE), that is,
if x is a character vector with no NAs and sep a single
string, then unstrsplit(strsplit(x, split=sep, fixed=TRUE), sep)
is identical to x. A notable exception to this though is when
strsplit finds a match at the end of a string, in which case the
last element of the output (which should normally be an empty string)
is not returned (see ?strsplit for the details).
A character vector with one string per list element in x.
Hervé Pagès
The strsplit function in the base
package.
x <- list(A=c("abc", "XY"), B=NULL, C=letters[1:4])
unstrsplit(x)
unstrsplit(x, sep=",")
unstrsplit(x, sep=" => ")
data(islands)
x <- names(islands)
y <- strsplit(x, split=" ", fixed=TRUE)
x2 <- unstrsplit(y, sep=" ")
stopifnot(identical(x, x2))
## But...
names(x) <- x
y <- strsplit(x, split="in", fixed=TRUE)
x2 <- unstrsplit(y, sep="in")
y[x != x2]
## In other words: strsplit() behavior sucks :-/Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.