If you know the associated numeric values for the Japanese characters, the associated regular expression becomes relatively simple.
If you look at: http://www.rikai.com/library/kanjitables/kanji_codes.unicode.shtml you will see a table for all the Japanese character unicode values, so if you just want to check for the Hiragana/Katakana alphabets, your regex becomes
[\u3041 - \u309F]* | [\u30A0 - \u30FF]*
note: perl and pcre do not support \u, instead use \x{####}, also this regex will only identify whether some string has a regex already contained within it. It does not also check for Kanji characters
You may also find http://www.regular-expressions.info/unicode.html useful.
Yes, it is possible to validate a string using a regular expression to ensure it is not empty.
In programming, a regular expression is an expression that explains a pattern for a string. A string matches a regular expression if that string follows the pattern of that regular expression. For example, you may want to create an account system, allowing usernames to only have uppercase and lowercase letters, and numbers. While a user is registering, you can check their desired username against a regular expression involving only alphanumeric characters (A-Z, a-z, 0-9). If it matches, then the username is valid to your requests. If it does not, the user has put in a character that does not follow the pattern of the regular expression. In regular expressions, you can match certain characters, match a certain quanity of characters, match the casing of characters (or just ignore it overall), and plenty more. The syntax of a regular expression varies throughout every programming language, but Perl is often used due to its wide variety of options. Perl is also incorporated into many web languages, such as PHP, making regular expressions less of a hassle. This is an example of a Perl regular expression, allowing a string with only alphanumeric characters (any character case), and an infinite length (except for a string with no length or no characters, in which the regular expression does not match the string): /^(?i)[a-z0-9]+$/
a period means 'any single character'. A period followed by an asterisk means 'zero or more characters'.
In programming, a regular expression is an expression that explains a pattern for a string. A string matches a regular expression if that string follows the pattern of that regular expression. For example, you may want to create an account system, allowing usernames to only have uppercase and lowercase letters, and numbers. While a user is registering, you can check their desired username against a regular expression involving only alphanumeric characters (A-Z, a-z, 0-9). If it matches, then the username is valid to your requests. If it does not, the user has put in a character that does not follow the pattern of the regular expression. In regular expressions, you can match certain characters, match a certain quanity of characters, match the casing of characters (or just ignore it overall), and plenty more. The syntax of a regular expression varies throughout every programming language, but Perl is often used due to its wide variety of options. Perl is also incorporated into many web languages, such as PHP, making regular expressions less of a hassle. This is an example of a Perl regular expression, allowing a string with only alphanumeric characters (any character case), and an infinite length (except for a string with no length or no characters, in which the regular expression does not match the string): /^(?i)[a-z0-9]+$/
You should probably use regular expressions. For example, the following will check that the String s has only English (Latin) characters in it:boolean hasOnlyLatin = s.matches("^[a-zA-Z]*$");Learning to use regular expressions is scary at first, but worthwhile. See the related links for some information about regular expressions in Java.
py4everybody regular expression answers autograde 11.2
Regular expressions and context-free grammars are both formal languages used in computer science to describe patterns in strings. Regular expressions are simpler and more limited in their expressive power, while context-free grammars are more complex and can describe a wider range of patterns. Regular expressions can be converted into context-free grammars, but not all context-free grammars can be represented by regular expressions.
The complement of a regular language is the set of all strings that are not in the original language. In terms of regular expressions, the complement of a regular language can be represented by negating the regular expression that defines the original language.
Regular expressions can be used to find patterns within data. Beyond that the subject of Regular expressions gets extremely complicated very fast, I suggest you purchase a book on the subject and read it... twice.. http://www.amazon.com/Mastering-Regular-Expressions-Jeffrey-Friedl/dp/0596528124/ref=sr_1_1?ie=UTF8&qid=1345423498&sr=8-1&keywords=regular+expressions
To simplify regular expressions using a regex simplifier tool, you can input your complex regular expression into the tool, and it will analyze and simplify it for you. This can help make your regular expression more concise and easier to understand.
The time complexity of regular expressions (regex) operations is typically O(n), where n is the length of the input string being processed.
You use instead of OR