Return the first visual character(s) of a string.
APACHE-2.0 License
Return the first character(s) of a string.
npm install @stdlib/string-first
Alternatively,
script
tag without installation and bundlers, use the ES Module available on the esm
branch (see README).deno
branch (see README for usage intructions).umd
branch (see README).The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
var first = require( '@stdlib/string-first' );
Returns the first character(s) of a string.
var out = first( 'last man standing' );
// returns 'l'
out = first( 'Hidden Treasures' );
// returns 'H'
The function supports the following options:
mode: type of characters to return. Must be one of the following:
'grapheme'
: grapheme clusters. Appropriate for strings containing visual characters which can span multiple Unicode code points (e.g., emoji).'code_point'
: Unicode code points. Appropriate for strings containing visual characters which are comprised of more than one Unicode code unit (e.g., ideographic symbols and punctuation and mathematical alphanumerics).'code_unit'
: UTF-16 code units. Appropriate for strings containing visual characters drawn from the basic multilingual plane (BMP) (e.g., common characters, such as those from the Latin, Greek, and Cyrillic alphabets).Default: 'grapheme'
.
By default, the function returns the first character. To return the first n
characters, provide a second argument specifying the number of characters to return.
var out = first( 'foo bar', 5 );
// returns 'foo b'
out = first( 'foo bar', 10 );
// returns 'foo bar'
mode
option.var first = require( '@stdlib/string-first' );
var str = first( 'last man standing' );
// returns 'l'
str = first( 'presidential election' );
// returns 'p'
str = first( 'javaScript' );
// returns 'j'
str = first( 'Hidden Treasures' );
// returns 'H'
str = first( 'The Last of the Mohicans', 5 );
// returns 'The L'
str = first( '๐ถ๐ฎ๐ท๐ฐ๐ธ', 2 );
// returns '๐ถ๐ฎ'
str = first( '๐ถ๐ฎ๐ท๐ฐ๐ธ', 10 );
// returns '๐ถ๐ฎ๐ท๐ฐ๐ธ'
To use as a general utility, install the CLI package globally
npm install -g @stdlib/string-first-cli
Usage: first [options] [<string>]
Options:
-h, --help Print this message.
-V, --version Print the package version.
--n num Number of characters to return. Default: 1.
--split sep Delimiter for stdin data. Default: '/\\r?\\n/'.
--mode mode Type of character to return. Default: 'grapheme'.
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' | first --split /\r?\n/
# Escaped...
$ echo -n $'beep\nboop' | first --split /\\r?\\n/
The implementation ignores trailing delimiters.
$ first beep
b
To use as a standard stream,
$ echo -n 'beep\nboop' | first --n=2
be
bo
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 'beep\tboop' | first --split '\t'
b
b
@stdlib/string-remove-first
: remove the first character(s) of a string.
@stdlib/string-last
: return the last character(s) of a string.
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.
See LICENSE.
Copyright ยฉ 2016-2024. The Stdlib Authors.