lua-string-format

formatted output conversion module with asprintf and snprintf.

Installation

luarocks install string-format

Usage

local format = require('string.format')

-- To print a date and time in the form “Sunday, July 3, 10:02”, where weekday and month are strings
local weekday, month, day, hour, min = 'Sunday', 'July', 3, 10, 2
local s = format('%s, %s %d, %.2d:%.2d\n', weekday, month, day, hour, min)
print(s) --> Sunday, July 3, 10:02

-- To print pi to five decimal places:
s = format('pi = %.5f\n', 4 * math.atan(1.0))
print(s) --> pi = 3.14159

s, unused, nunused = format( fmt [, ... ] )

converts the specified arguments to formatted output using asprintf and snprintf, and returns the result string and unused arguments.

the format fmt specifiers are the same as snprintf of the C standard library except for the following specifiers.

• flags: #, 0, -, +, space
• width: number, *
• precision: number, *
• length: hh, h, l, ll, j, z, t, L
• specifiers: d, i, o, u, x, X, e, E, f, F, g, G, a, A, c, s, p, q, m, %
  • the format specifier s converts the argument to a string.
  • the format specifier q converts the argument to a string and escaping the control characters and double quotes " with a backslash \, and then enclosing it in double quotes ".

please see the manual page of man 3 printf for more information.

Parameters

• fmt:string: the format string that describes the format of the output.
• ...:any: the arguments to be converted to formatted output according to the format string.

Returns

• s:string: the formatted output string.
• unused:table?: the unused arguments placed in the table.
• nunused:integer?: the number of unused arguments.

License

MIT License