Left Pad
Left pad a string.
Installation
npm install @stdlib/string-left-pad
Usage
var lpad = require( '@stdlib/string-left-pad' );
lpad( str, len[, pad] )
Left pads a string
such that the padded string
has a length
of at least len
.
var str = lpad( 'a', 5 );
// returns ' a'
By default, an input string
is padded with spaces
. To pad with a different character or sequence of characters, provide a pad
string.
var str = lpad( 'beep', 10, 'b' );
// returns 'bbbbbbbeep'
str = lpad( 'boop', 12, 'beep' );
// returns 'beepbeepboop'
Notes
-
An output
string
is not guaranteed to have a length of exactlylen
, but to have alength
of at leastlen
. To generate a paddedstring
having alength
equal tolen
var str = lpad( 'boop', 10, 'beep' ); // => length 12 // returns 'beepbeepboop' str = str.substring( str.length-10 ); // => length 10 // returns 'epbeepboop'
Examples
var round = require( '@stdlib/math-base-special-round' );
var randu = require( '@stdlib/random-base-randu' );
var lpad = require( '@stdlib/string-left-pad' );
var str = 'beep';
var n;
var i;
for ( i = 0; i < 100; i++ ) {
n = round( randu()*10 ) + str.length;
console.log( lpad( str, n, 'b' ) );
}
CLI
Installation
To use the module as a general utility, install the module globally
npm install -g @stdlib/string-left-pad
Usage
Usage: lpad [options] [<string>] --len=<length>
Options:
-h, --help Print this message.
-V, --version Print the package version.
--len length Minimum string length.
--pad str String used to pad. Default: ' '.
--split sep Delimiter for stdin data. Default: '/\\r?\\n/'.
Notes
-
If the split separator is a regular expression, ensure that the
split
option is either properly escaped or enclosed in quotes.# Not escaped... $ echo -n $'beep\nboop' | lpad -len 8 --split /\r?\n/ # Escaped... $ echo -n $'beep\nboop' | lpad -len 8 --split /\\r?\\n/
-
The implementation ignores trailing delimiters.
Examples
$ lpad beep --len 10 --pad b
bbbbbbbeep
To use as a standard stream,
$ echo -n 'beep' | lpad --len 8
beep
By default, when used as a standard stream, the implementation assumes newline-delimited data. To specify an alternative delimiter, set the split
option.
$ echo -n 'boop\tbeep' | lpad --len 8 --split '\t'
boop
beep
See Also
-
@stdlib/string/pad
: pad a string. -
@stdlib/string/right-pad
: right pad a string.
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
License
See LICENSE.
Copyright
Copyright © 2016-2022. The Stdlib Authors.