format

Insert supplied variable values into a format string.

Installation

npm install @stdlib/string-format

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch.
• If you are using Deno, visit the deno branch.
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch.

Usage

var format = require( '@stdlib/string-format' );

format( str, ...args )

Inserts supplied variable values into a format string.

var str = 'Hello, %s! My name is %s.';
var out = format( str, 'world', 'Bob' );
// returns 'Hello, world! My name is Bob.'

The format string is a string literal containing zero or more conversion specifications, each of which results in a string value being inserted to the output string. A conversion specification consists of a percent sign (%) followed by one or more of the following flags, width, precision, and conversion type characters:

type	description	notes
s	string
c	character
d	signed decimal integer
i	signed decimal integer
u	unsigned decimal integer
b	unsigned binary integer
o	unsigned octal integer
x	unsigned hexadecimal
X	unsigned hexadecimal
f	floating point
e	floating point
E	floating point
g	floating point
G	floating point

Examples

var format = require( '@stdlib/string-format' );

var out = format( '%s %s!', 'Hello', 'World' );
// returns 'Hello World!'

out = format( 'Pi: ~%.2f', 3.141592653589793 );
// returns 'Pi: ~3.14'

out = format( '%-10s %-10s', 'a', 'b' );
// returns 'a       b       '

out = format( '%10s %10s', 'a', 'b' );
// returns '       a       b'

out = format( '%2$s %1$s %3$s', 'b', 'a', 'c' );
// returns 'a b c'

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Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2022. The Stdlib Authors.