logf function — logf • toscutil

Prints a formatted string with optional prefix and end string. The default prefix is a grey timestamp and the default end is a newline character, which is useful for logging messages. All defaults can be set globally using options(). For details see 'Examples'.

Usage

logf(
  fmt,
  ...,
  file = .Options$toscutil.logf.file %||% "",
  append = .Options$toscutil.logf.append %||% FALSE,
  prefix = .Options$toscutil.logf.prefix %||% function() now_ms(usetz = FALSE, color =
    fg$GREY),
  sep1 = .Options$toscutil.logf.sep1 %||% " ",
  sep2 = .Options$toscutil.logf.sep2 %||% "",
  end = .Options$toscutil.logf.end %||% "\n"
)

Arguments

...: Arguments to be passed to sprintf for string formatting.
file: A file() connection object or a string naming the file to print to. If "" (the default), output is printed to STDOUT unless redirected by sink().
append: Logical. If TRUE, the output is appended to the file. If FALSE, the file is overwritten.
prefix: A function returning a string to be used as the prefix.
sep1: A string to be used as the separator between the prefix and the formatted string.
sep2: A string to be used as the separator between the formatted string and the end.
end: A string to be used as the end of the message.

Value

No return value. This function is called for its side effect of printing a message.

Examples

logf("Hello, %s!", "world")
#> 2024-07-11 13:42:50.44 Hello, world!
logf("Goodbye", prefix = function() "", sep1 = "", end = "!\n")
#> Goodbye!
local({
     opts <- options(toscutil.logf.prefix = function() "LOG:", toscutil.logf.end = "\n")
     on.exit(options(opts))
     logf("Hello, %s!", "world")
})
#> LOG: Hello, world!