Happy new Year!
Here is a slightly changed version of format.char(), which really speeds up
for big data.
Regards
Jens Oehlschlägel-Akiyoshi
format.char.old <- format.char
format.char <-
function (x, width = NULL, flag = "-")
{
if (is.null(x))
return("")
if (!is.character(x)) {
warning("format.char: coercing 'x' to
'character'")
x <- as.character(x)
}
if (is.null(width) && flag == "-")
return(format(x))
at <- attributes(x)
nc <- nchar(x)
if (is.null(width))
width <- max(nc)
else if (width < 0) {
flag <- "-"
width <- -width
}
# start of accelerate
no <- pmax(0, width - nc)
tab <- unique(no)
tabpad <- sapply(tab+1, function(no) paste(character(no), collapse =
"
"))
pad <- tabpad[match(no, tab)]
# end of accelerate
r <- if (flag == "-")
paste(x, pad, sep = "")
else paste(pad, x, sep = "")
if (!is.null(at))
attributes(r) <- at
r
}
> system.time(format.char(character(10), width=30))
[1] 0.01 0.00 0.01 NA NA> system.time(format.char.old(character(10), width=30))
[1] 0.01 0.00 0.01 NA NA
> system.time(format.char(character(100000), width=30))
[1] 3.90 0.02 3.92 NA NA> system.time(format.char.old(character(100000), width=30))
[1] 92.33 0.35 92.69 NA NA
> system.time(format.char(character(1000), width=1:1000))
[1] 2.69 0.00 2.68 NA NA> system.time(format.char.old(character(1000), width=1:1000))
[1] 2.55 0.00 2.55 NA NA
> system.time(format.char(character(100000), width=1:1000))
[1] 28.71 0.00 28.72 NA NA> system.time(format.char.old(character(100000), width=1:1000))
Error: heap memory (65536 Kb) exhausted [needed 0 Kb more]
See "help(Memory)" on how to increase the heap size.
Timing stopped at: 269.1 0.28 269.56 NA NA
--
Dr. Jens Oehlschlägel-Akiyoshi
MD FACTORY GmbH
Bayerstrasse 21
80335 München
Tel.: 089 545 28-27
Fax.: 089 545 28-10
http://www.mdfactory.de
Standard Disclaimers: Opinions expressed here are personal
and are not otherwise represented.
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