Anonymous user
Truncate a file: Difference between revisions
→{{header|Racket}}
(add Standard ML) |
|||
Line 995:
f.truncate(length)
return True
</lang>
=={{header|R}}==
<lang R>
truncate_file <- function(filename, n_bytes) {
# check file exists and size is greater than n_bytes
stopifnot(
"file does not exist"= file.exists(filename),
"not enough bytes in file"= file.size(filename) >= n_bytes
)
# read bytes from input file
input.con <- file(filename, "rb")
bindata <- readBin(input.con, integer(), n=n_bytes/4)
close(input.con)
# write bytes to temporary file
tmp.filename <- tempfile()
output.con <- file(tmp.filename, "wb")
writeBin(bindata, output.con)
close(output.con)
# double check that everything worked before overwriting original file
stopifnot(
"temp file is not expected size"= file.size(tmp.filename) == n_bytes
)
# overwrite input file with temporary file
file.rename(tmp.filename, filename)
}
</lang>
| |||