Contents

debugPrint(_:separator:terminator:to:)

Writes the textual representations of the given items most suitable for debugging into the given output stream.

Declaration

func debugPrint<Target>(_ items: Any..., separator: String = " ", terminator: String = "\n", to output: inout Target) where Target : TextOutputStream

Parameters

  • items:

    Zero or more items to print.

  • separator:

    A string to print between each item. The default is a single space (" ").

  • terminator:

    The string to print after all items have been printed. The default is a newline ("\n").

  • output:

    An output stream to receive the text representation of each item.

Discussion

You can pass zero or more items to the debugPrint(_:separator:terminator:to:) function. The textual representation for each item is the same as that obtained by calling String(reflecting: item). The following example prints a closed range of integers to a string:

var range = "My range: "
debugPrint(1...5, to: &range)
// range == "My range: ClosedRange(1...5)\n"

To print the items separated by something other than a space, pass a string as separator.

var separated = ""
debugPrint(1.0, 2.0, 3.0, 4.0, 5.0, separator: " ... ", to: &separated)
// separated == "1.0 ... 2.0 ... 3.0 ... 4.0 ... 5.0\n"

The output from each call to debugPrint(_:separator:terminator:to:) includes a newline by default. To print the items without a trailing newline, pass an empty string as terminator.

var numbers = ""
for n in 1...5 {
    debugPrint(n, terminator: "", to: &numbers)
}
// numbers == "12345"

See Also

Printing and Dumping