Search results
Results from the WOW.Com Content Network
String functions are used in computer programming languages to manipulate a string or query information about a string (some do both).. Most programming languages that have a string datatype will have some string functions although there may be other low-level ways within each language to handle strings directly.
In C, the functions strcmp and memcmp perform a three-way comparison between strings and memory buffers, respectively. They return a negative number when the first argument is lexicographically smaller than the second, zero when the arguments are equal, and a positive number otherwise.
Language feature comparison (part 2) Directives [Note 1] Conditionals Atomic groups [Note 2] Named capture [Note 3] Comments Embedded code Unicode property support [4] Balancing groups [Note 4] Variable-length look-behinds [Note 5] Boost.Regex: Yes Yes Yes Yes Yes No Some [Note 6] No No Boost.Xpressive: Yes No Yes Yes Yes No No No No CL-PPCRE ...
case class name(«var» name: type, ...) (val 1, val 2, val 3, ...) abstract class name case class Foo(«parameters») extends name case class Bar(«parameters») extends name ... or abstract class name case object Foo extends name case object Bar extends name ... or a combination of case classes and case objects Windows PowerShell: OCaml
Some other programming languages have varying case sensitivity; in PHP, for example, variable names are case-sensitive but function names are not case-sensitive. This means that if a function is defined in lowercase, it can be called in uppercase, but if a variable is defined in lowercase, it cannot be referred to in uppercase.
A classic example of a problem which a regular grammar cannot handle is the question of whether a given string contains correctly nested parentheses. (This is typically handled by a Chomsky Type 2 grammar, also termed a context-free grammar .)
The std::string class is the standard representation for a text string since C++98. The class provides some typical string operations like comparison, concatenation, find and replace, and a function for obtaining substrings. An std::string can be constructed from a C-style string, and a C-style string can also be obtained from one. [7]
A parsing expression is a kind of pattern that each string may either match or not match.In case of a match, there is a unique prefix of the string (which may be the whole string, the empty string, or something in between) which has been consumed by the parsing expression; this prefix is what one would usually think of as having matched the expression.