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Character
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Description
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\
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A backslash nullifies, or escapes, the special treatment of special characters so that the special character can be matched like a normal letter. A pair of backslashes is translated into one non-special backslash. For example:
match("ab$cd","ab$cd"); //returns 0
match("ab\$cd","ab$cd"); //returns 0 - the backslash is not escaped
match("ab\\$cd","ab$cd"); //returns 1 - the backslash and dollar sign are escaped
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< or ^
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A left angle bracket or a circumflex at the start of an expression is used to match the start of a line. For example:
match("<abc","abcdef"); //returns 1
match("<abc","defabc"); //returns 0
match("^abc","abcdef"); //returns 1
match("^abc","defabc"); //returns 0
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> or $
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A right angle bracket or a dollar sign at the end of the expression is used to match the end of a line. For example:
match("abc>","abcdef"); //returns 0
match("abc>","defabc"); //returns 1
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? or .
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A question mark or a period will match any one character in the same position. For example:
match("abc.def","abc#def"); //returns 1
match("colou?r","colouXr"); //returns 1
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:x
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A colon specifies a group of characters to be matched, indicated by the character that follows immediately after.
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:a
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Sets the match to letters. For example:
match("ab:acd","ab#cd"); //returns 0
match("ab:acd","abxyzcd"); //returns 0
match("ab:acd","abxcd"); //returns 1
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:d
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Sets the match to numeric characters. For example:
match("ab:dcd","ab3cd"); //returns 1
match("ab:dcd","ab123cd"); //returns 0
match("ab:dcd","abcd"); //returns 0
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:n
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Sets the match to alphanumeric characters. For example:
match("ab:ncd","ab%cd"); //returns 0
match("ab:ncd","ab9cd"); //returns 1
match("ab:ncd","abXcd"); //returns 1
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:SPACE
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Where SPACE is the character ' '. Sets the match to blanks, tabulations, and control characters such as Enter (new line). For example:
match("ab: cd","ab cd"); //returns 1
match("ab: cd","ab\ncd"); //returns 1
match("ab: cd","ab\tcd"); //returns 1
match("ab: cd","ab cd"); //returns 0 - only the first space is matched
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*
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An expression followed by an asterisk requires a match for zero, one, or more occurrences of the preceding expression. For example:
match("abc*d","abd"); //returns 1
match("abc*d","abcd"); //returns 1
match("abc*d","abcccd"); //returns 1
match("abc*d","abxd"); //returns 0
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+
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An expression followed by a plus sign requires a match for one or more occurrences of the preceding expression. For example:
match("abc+d","abd"); //returns 0
match("abc+d","abcd"); //returns 1
match("abc+d","abcccd"); //returns 1
match("abc+d","abxd"); //returns 0
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-
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An expression followed by a minus sign requires a match for zero or one occurrence of the preceding expression. In other words, the preceding expression is optional. For example:
match("colou-r","color"); //returns 1
match("colou-r","colour"); //returns 1
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[]
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Matches a single character with any character contained within the brackets.A range of characters can be specified by two characters separated by a minus sign. For example, [a-z] matches all letters between a and z, [0-9] matches a digit, [0-9a-f] matches a hexadecimal digit.
match("[abc]","apple"); //returns 1 - matches the 'a' in apple
match("[abc]","kiwi"); //returns 0 - kiwi does not contain an a, b, or c
match("gr[ae]y","grey"); //returns 1 - also matches "gray"
match("gr[ae]y","graey"); //returns 0 - only one character between "gr" and "y" is matched.
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[^]
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If the first character in a text within square brackets is a circumflex (^), the expression matches all characters except those contained within the brackets.
match("[^bc]at","bat"); //returns 0
match("[^bc]at","hat"); //returns 1
match("[^abc]","bat"); //returns 1 - anything but a, b, or c is matched. The t is matched
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