Compose a message as a single substring from a character vector
This is a utility function to make it easier to automatically compose informative error and warning messages without using too many characters.
createMessage(x, width.cutoff=45, default='x',
collapse='; ', endchars='...')x |
input for |
width.cutoff |
maximum number of characters from x to
return in a single string. This differs
from the |
default |
character string to return if
|
collapse |
|
endchars |
a character string to indicate that part of the input string(s) was truncated. |
x. <- paste(..., collapse='; ')
nchx <- nchar(x.)
maxch <- (maxchar-nchar(endchars))
if(nchx>maxch){
x2 <- substring(x., 1, maxch)
x. <- paste0(x2, endchar)
}
a character string with at most
width.cutoff characters.
Spencer Graves
##
## 1. typical use
##
tstVec <- c('Now', 'is', 'the', 'time')
msg <- createMessage(tstVec, 9, collapse=':',
endchars='//')
all.equal(msg, 'Now:is://')
##
## 2. in a function
##
tstFn <- function(cl)createMessage(deparse(cl), 9)
Cl <- quote(plot(1:3, y=4:6, col='red', main='Title'))
msg0 <- tstFn(Cl)
# check
msg. <- 'plot(1...'
all.equal(msg0, msg.)
##
## 3. default
##
y <- createMessage(character(3), default='y')
all.equal(y, 'y')Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.