.verb.md

April 7, 2020 · View on GitHub

Usage

var posix = require('{%= name %}');
console.log(posix.alpha);
//=> 'A-Za-z'

POSIX Character classes

The POSIX standard supports the following classes or categories of charactersh (note that classes must be defined within brackets)1:

POSIX classEquivalent toMatches
[:alnum:][A-Za-z0-9]digits, uppercase and lowercase letters
[:alpha:][A-Za-z]upper- and lowercase letters
[:ascii:][\x00-\x7F]ASCII characters
[:blank:][ \t]space and TAB characters only
[:cntrl:][\x00-\x1F\x7F]Control characters
[:digit:][0-9]digits
[:graph:][^ [:cntrl:]]graphic characters (all characters which have graphic representation)
[:lower:][a-z]lowercase letters
[:print:][[:graph] ]graphic characters and space
[:punct:]``[-!"#$%&'()*+,./:;<=>?@[]^_`{}~]``
[:space:][ \t\n\r\f\v]all blank (whitespace) characters, including spaces, tabs, new lines, carriage returns, form feeds, and vertical tabs
[:upper:][A-Z]uppercase letters
[:word:][A-Za-z0-9_]word characters
[:xdigit:][0-9A-Fa-f]hexadecimal digits

Examples

  • a[[:digit:]]b matches a0b, a1b, ..., a9b.
  • a[:digit:]b is invalid, character classes must be enclosed in brackets
  • [[:digit:]abc] matches any digit, as well as a, b, and c.
  • [abc[:digit:]] is the same as the previous, matching any digit, as well as a, b, and c
  • [^ABZ[:lower:]] matches any character except lowercase letters, A, B, and Z.

Footnotes

  1. table and examples are based on the WikiBooks page for Regular Expressions/POSIX Basic Regular Expressions, which is available under the Creative Commons Attribution-ShareAlike License.