applied, see below.
A field width or precision, or both, may be indicated by an
asterisk "*" instead of a digit string. In this case, a
Number argument supplies the field width or precision. A
negative field width is treated as a left adjustment flag
followed by a positive field width; a negative precision is
treated as though it were missing. Example: >vim
echo printf("%d: %.*s", nr, width, line)
< This limits the length of the text used from "line" to
"width" bytes.
If the argument to be formatted is specified using a
positional argument specifier, and a '*' is used to indicate
that a number argument is to be used to specify the width or
precision, the argument(s) to be used must also be specified
using a {n$} positional argument specifier. See |printf-$|.
The conversion specifiers and their meanings are:
*printf-d* *printf-b* *printf-B* *printf-o* *printf-x* *printf-X*
dbBoxX The Number argument is converted to signed decimal (d),
unsigned binary (b and B), unsigned octal (o), or
unsigned hexadecimal (x and X) notation. The letters
"abcdef" are used for x conversions; the letters
"ABCDEF" are used for X conversions. The precision, if
any, gives the minimum number of digits that must
appear; if the converted value requires fewer digits, it
is padded on the left with zeros. In no case does a
non-existent or small field width cause truncation of a
numeric field; if the result of a conversion is wider
than the field width, the field is expanded to contain
the conversion result.
The 'h' modifier indicates the argument is 16 bits.
The 'l' modifier indicates the argument is a long
integer. The size will be 32 bits or 64 bits
depending on your platform.
The "ll" modifier indicates the argument is 64 bits.
The b and B conversion specifiers never take a width
modifier and always assume their argument is a 64 bit
integer.
Generally, these modifiers are not useful. They are
ignored when type is known from the argument.
i alias for d
D alias for ld
U alias for lu
O alias for lo
*printf-c*
c The Number argument is converted to a byte, and the
resulting character is written.
*printf-s*
s The text of the String argument is used. If a
precision is specified, no more bytes than the number
specified are used.
If the argument is not a String type, it is
automatically converted to text with the same format
as ":echo".
*printf-S*
S The text of the String argument is used. If a
precision is specified, no more display cells than the
number specified are used.
*printf-f* *E807*
f F The Float argument is converted into a string of the
form 123.456. The precision specifies the number of
digits after the decimal point. When the precision is
zero the decimal point is omitted. When the precision
is not specified 6 is used. A really big number
(out of range or dividing by zero) results in "inf"
or "-inf" with %f (INF or -INF with %F).
"0.0 / 0.0" results in "nan" with %f (NAN with %F).
Example: >vim
echo printf("%.2f", 12.115)
< 12.12
Note that roundoff depends on the system libraries.
Use |round()| when in doubt.
*printf-e* *printf-E*
e E The Float argument is converted into a string of the
form 1.234e+03 or 1.234E+03 when using 'E'. The
precision specifies the number of digits after the
decimal point, like with 'f'.
*printf-g* *printf-G*
g G The Float argument is converted like with 'f' if the
value is between 0.001 (inclusive) and 10000000.0
(exclusive). Otherwise 'e' is used for 'g' and 'E'
for 'G'. When no precision is specified superfluous
zeroes and '+' signs are removed, except for the zero
immediately after the decimal point. Thus 10000000.0
results in 1.0e7.
*printf-%*
% A '%' is written. No argument is converted. The
complete conversion specification is "%%".