Regular Expressions Cookbook, 2nd Edition

2.7. Unicode Code Points, Categories, Blocks, and Scripts

Problem

Use a regular expression to find the trademark sign (™) by specifying its Unicode code point rather than copying and pasting an actual trademark sign. If you like copy and paste, the trademark sign is just another literal character, even though you cannot type it directly on your keyboard. Literal characters are discussed in Recipe 2.1.

Create a regular expression that matches any character is in the “Currency Symbol” Unicode category.

Create a regular expression that matches any character in the “Greek Extended” Unicode block.

Create a regular expression that matches any character that, according to the Unicode standard, is part of the Greek script.

Create a regular expression that matches a grapheme, or what is commonly thought of as a character: a base character with all its combining marks.

Solution

Unicode code point

\u2122

Regex options: None

Regex flavors: .NET, Java, JavaScript, Python, Ruby 1.9

\U00002122

Regex options: None

Regex flavors: Python

These regexes work in Python 2.x only when quoted as Unicode strings: u"\u2122" or u"\U00002122".

\x{2122}

Regex options: None

Regex flavors: Java 7, PCRE, Perl

PCRE must be compiled with UTF-8 support; in PHP, turn on UTF-8 support with the /u pattern modifier.

\u{2122}

Regex options: None

Regex flavors: Ruby 1.9

Ruby 1.8 does not support Unicode regular expressions.

Unicode category

\p{Sc}

Regex options: None

Regex flavors: .NET, Java, XRegExp, PCRE, Perl, Ruby 1.9

PCRE must be compiled ...