Method: IO#print

Defined in:

io.c

#print(*objects) ⇒ nil

Writes the given objects to the stream; returns nil. Appends the output record separator $OUTPUT_RECORD_SEPARATOR ($\), if it is not nil. See Line IO.

With argument objects given, for each object:

• Converts via its method to_s if not a string.

• Writes to the stream.

• If not the last object, writes the output field separator $OUTPUT_FIELD_SEPARATOR ($,) if it is not nil.

With default separators:

f = File.open('t.tmp', 'w+')
objects = [0, 0.0, Rational(0, 1), Complex(0, 0), :zero, 'zero']
p $OUTPUT_RECORD_SEPARATOR
p $OUTPUT_FIELD_SEPARATOR
f.print(*objects)
f.rewind
p f.read
f.close

Output:

nil
nil
"00.00/10+0izerozero"

With specified separators:

$\ = "\n"
$, = ','
f.rewind
f.print(*objects)
f.rewind
p f.read

Output:

"0,0.0,0/1,0+0i,zero,zero\n"

With no argument given, writes the content of $_ (which is usually the most recent user input):

f = File.open('t.tmp', 'w+')
gets # Sets $_ to the most recent user input.
f.print
f.close

Returns:

• (nil)

# File 'io.c', line 8732

VALUE
rb_io_print(int argc, const VALUE *argv, VALUE out)
{
    int i;
    VALUE line;

    /* if no argument given, print `$_' */
    if (argc == 0) {
        argc = 1;
        line = rb_lastline_get();
        argv = &line;
    }
    if (argc > 1 && !NIL_P(rb_output_fs)) {
        rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
    }
    for (i=0; i<argc; i++) {
        if (!NIL_P(rb_output_fs) && i>0) {
            rb_io_write(out, rb_output_fs);
        }
        rb_io_write(out, argv[i]);
    }
    if (argc > 0 && !NIL_P(rb_output_rs)) {
        rb_io_write(out, rb_output_rs);
    }

    return Qnil;
}