StringExpression

Usage

• ~~ ~~ ... or StringExpression[, , ... ] represents a sequence of strings and symbolic string objects .

Notes

• "

" ~~ "

" ~~ ... yields an ordinary string obtained by concatenating the characters in the "

• The following objects can appear in StringExpression:

"string"	a literal string of characters
_	any single character
__	any substring of one or more characters
___	any substring of zero or more characters
x_, x__, x___	substrings given the name x
x:pattern	pattern given the name x
pattern..	pattern repeated one or more times
pattern...	pattern repeated zero or more times
{, , ... } or \| \| ...	a pattern matching at least one of the
patt /; cond	a pattern for which cond evaluates to True
pattern ? test	a pattern for which test yields True for each character
Whitespace	a sequence of whitespace characters
NumberString	the characters of a number
charobj	an object representing a character class (see below)
RegularExpression["regexp"]	substring matching a regular expression
StringExpression[... ]	an arbitrary string expression

• The following represent classes of characters:

{"", "", ... }	any of the ""
Characters[" ... "]	any of the ""
CharacterRange["", ""]	any character in the range "" to ""
DigitCharacter	digit 0-9
LetterCharacter	letter
WhitespaceCharacter	space, newline, tab or other whitespace character
WordCharacter	letter or digit
Except[p]	any character except ones matching p

• The following represent positions in strings:

StartOfString	start of the whole string
EndOfString	end of the whole string
StartOfLine	start of a line
EndOfLine	end of a line
WordBoundary	boundary between word characters and others
Except[WordBoundary]	anywhere except a word boundary

• When constructs like __ or .. are present, there may be several different ways in which a given StringExpression can match a particular string.

• By default, Mathematica will use the one that makes pattern elements that appear earlier in the StringExpression match the longest possible substrings.

• The following determine which match will be used if there are several possibilities:

ShortestMatch[p]	the shortest consistent match for p
LongestMatch[p]	the longest consistent match for p (default)

• In matching ordinary expressions instead of strings, the shortest instead of the longest consistent match is used.

• StringExpression objects can be used in many string manipulation functions, including StringReplace, StringCases, StringSplit, StringMatchQ.

• StringExpression has attributes Flat and OneIdentity.

• See Section 2.8.4.

• See also: RegularExpression, String, StringJoin.

• New in Version 5.1.

Further Examples