@stdlib/string-left-pad
v0.2.2
Published
Left pad a string.
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lpad
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 a Unicode "space" character (U+0020). 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 exactly
len
, but to have a length of at leastlen
. To generate a padded string having a length equal tolen
var str = lpad( 'boop', 10, 'beep' ); // => length 12 // returns 'beepbeepboop' str = str.substring( str.length-10 ); // => length 10 // returns 'epbeepboop'
This function differs from
String.prototype.padStart
in the following ways:- The function is not guaranteed to return a string having a length exactly equal to
len
(as explained above). - The function does not truncate
pad
(from the end) in order to ensure the returned string has lengthlen
.
To replicate
String.prototype.padStart
truncation behaviorvar floorb = require( '@stdlib/math-base-special-floorb' ); function padStart( str, len, pad ) { var n; if ( len <= str.length ) { return str; } n = floorb( len-str.length, 1, pad.length ) + str.length; return pad.substring( 0, len-n ) + lpad( str, n, pad ); } var str = padStart( 'boop', 10, 'beep' ); // returns 'bebeepboop'
- The function is not guaranteed to return a string having a length exactly equal to
Examples
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var lpad = require( '@stdlib/string-left-pad' );
var str = 'beep';
var i;
for ( i = 0; i < 100; i++ ) {
console.log( lpad( str, discreteUniform( str.length, str.length+10 ), 'b' ) );
}
See Also
@stdlib/string-left-pad-cli
: CLI package for use as a command-line utility.@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 © 2016-2024. The Stdlib Authors.